/*************************************************************************************

   Extended WPF Toolkit

   Copyright (C) 2007-2013 Xceed Software Inc.

   This program is provided to you under the terms of the Microsoft Public
   License (Ms-PL) as published at http://wpftoolkit.codeplex.com/license 

   For more features, controls, and fast professional support,
   pick up the Plus Edition at http://xceed.com/wpf_toolkit

   Stay informed: follow @datagrid on Twitter or Like http://facebook.com/datagrids

  ***********************************************************************************/

using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Controls;
using System.Windows;
using System.Windows.Data;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Windows.Input;
using System.Diagnostics;
using System.Windows.Documents;
using System.Globalization;
using System.Windows.Controls.Primitives;
using System.Reflection;

using System.Collections;
using System.Security;
using System.Security.Permissions;
using System.Windows.Automation;
using Xceed.Wpf.Toolkit.Primitives;

namespace Xceed.Wpf.Toolkit
{
  public class MaskedTextBox : ValueRangeTextBox
  {
    #region STATIC MEMBERS

    private static readonly char[] MaskChars = { '0', '9', '#', 'L', '?', '&', 'C', 'A', 'a', '.', ',', ':', '/', '$', '<', '>', '|', '\\' };

    private static char DefaultPasswordChar = '\0';

    private static string NullMaskString = "<>";

    private static string GetRawText( MaskedTextProvider provider )
    {
      return provider.ToString( true, false, false, 0, provider.Length );
    }

    public static string GetFormatSpecifierFromMask( string mask, IFormatProvider formatProvider )
    {
      List<int> notUsed;

      return MaskedTextBox.GetFormatSpecifierFromMask(
        mask,
        MaskedTextBox.MaskChars,
        formatProvider,
        true,
        out notUsed );
    }

    private static string GetFormatSpecifierFromMask(
      string mask,
      char[] maskChars,
      IFormatProvider formatProvider,
      bool includeNonSeparatorLiteralsInValue,
      out List<int> unhandledLiteralsPositions )
    {
      unhandledLiteralsPositions = new List<int>();

      NumberFormatInfo numberFormatInfo = NumberFormatInfo.GetInstance( formatProvider );

      StringBuilder formatSpecifierBuilder = new StringBuilder( 32 );

      // Space will be considered as a separator literals and will be included 
      // no matter the value of IncludeNonSeparatorLiteralsInValue.
      bool lastCharIsLiteralIdentifier = false;
      int i = 0;
      int j = 0;

      while( i < mask.Length )
      {
        char currentChar = mask[ i ];

        if( ( currentChar == '\\' ) && ( !lastCharIsLiteralIdentifier ) )
        {
          lastCharIsLiteralIdentifier = true;
        }
        else
        {
          if( ( lastCharIsLiteralIdentifier ) || ( Array.IndexOf( maskChars, currentChar ) < 0 ) )
          {
            lastCharIsLiteralIdentifier = false;

            // The currentChar was preceeded by a liteal identifier or is not part of the MaskedTextProvider mask chars.
            formatSpecifierBuilder.Append( '\\' );
            formatSpecifierBuilder.Append( currentChar );

            if( ( !includeNonSeparatorLiteralsInValue ) && ( currentChar != ' ' ) )
              unhandledLiteralsPositions.Add( j );

            j++;
          }
          else
          {
            // The currentChar is part of the MaskedTextProvider mask chars.  
            if( ( currentChar == '0' ) || ( currentChar == '9' ) || ( currentChar == '#' ) )
            {
              formatSpecifierBuilder.Append( '0' );
              j++;
            }
            else if( currentChar == '.' )
            {
              formatSpecifierBuilder.Append( '.' );
              j += numberFormatInfo.NumberDecimalSeparator.Length;
            }
            else if( currentChar == ',' )
            {
              formatSpecifierBuilder.Append( ',' );
              j += numberFormatInfo.NumberGroupSeparator.Length;
            }
            else if( currentChar == '$' )
            {
              string currencySymbol = numberFormatInfo.CurrencySymbol;

              formatSpecifierBuilder.Append( '"' );
              formatSpecifierBuilder.Append( currencySymbol );
              formatSpecifierBuilder.Append( '"' );

              for( int k = 0; k < currencySymbol.Length; k++ )
              {
                if( !includeNonSeparatorLiteralsInValue )
                  unhandledLiteralsPositions.Add( j );

                j++;
              }
            }
            else
            {
              formatSpecifierBuilder.Append( currentChar );

              if( ( !includeNonSeparatorLiteralsInValue ) && ( currentChar != ' ' ) )
                unhandledLiteralsPositions.Add( j );

              j++;
            }
          }
        }

        i++;
      }

      return formatSpecifierBuilder.ToString();
    }

    #endregion STATIC MEMBERS

    #region CONSTRUCTORS

    static MaskedTextBox()
    {
      MaskedTextBox.TextProperty.OverrideMetadata( typeof( MaskedTextBox ),
        new FrameworkPropertyMetadata(
        null,
        new CoerceValueCallback( MaskedTextBox.TextCoerceValueCallback ) ) );

      AutomationProperties.AutomationIdProperty.OverrideMetadata( typeof( MaskedTextBox ), new UIPropertyMetadata( "MaskedTextBox" ) );
    }

    public MaskedTextBox()
    {
      CommandManager.AddPreviewCanExecuteHandler( this, new CanExecuteRoutedEventHandler( this.OnPreviewCanExecuteCommands ) );
      CommandManager.AddPreviewExecutedHandler( this, new ExecutedRoutedEventHandler( this.OnPreviewExecutedCommands ) );

      this.CommandBindings.Add( new CommandBinding( ApplicationCommands.Paste, null, new CanExecuteRoutedEventHandler( this.CanExecutePaste ) ) );
      this.CommandBindings.Add( new CommandBinding( ApplicationCommands.Cut, null, new CanExecuteRoutedEventHandler( this.CanExecuteCut ) ) );
      this.CommandBindings.Add( new CommandBinding( ApplicationCommands.Copy, null, new CanExecuteRoutedEventHandler( this.CanExecuteCopy ) ) );
      this.CommandBindings.Add( new CommandBinding( EditingCommands.ToggleInsert, new ExecutedRoutedEventHandler( this.ToggleInsertExecutedCallback ) ) );

      this.CommandBindings.Add( new CommandBinding( EditingCommands.Delete, null, new CanExecuteRoutedEventHandler( this.CanExecuteDelete ) ) );
      this.CommandBindings.Add( new CommandBinding( EditingCommands.DeletePreviousWord, null, new CanExecuteRoutedEventHandler( this.CanExecuteDeletePreviousWord ) ) );
      this.CommandBindings.Add( new CommandBinding( EditingCommands.DeleteNextWord, null, new CanExecuteRoutedEventHandler( this.CanExecuteDeleteNextWord ) ) );

      this.CommandBindings.Add( new CommandBinding( EditingCommands.Backspace, null, new CanExecuteRoutedEventHandler( this.CanExecuteBackspace ) ) );

      System.Windows.DragDrop.AddPreviewQueryContinueDragHandler( this, new QueryContinueDragEventHandler( this.PreviewQueryContinueDragCallback ) );
      this.AllowDrop = false;
    }

    [System.Diagnostics.CodeAnalysis.SuppressMessage( "Microsoft.Performance", "CA1820:TestForEmptyStringsUsingStringLength" )]
    private void InitializeMaskedTextProvider()
    {
      string preInitializedText = this.Text;

      string mask = this.Mask;

      if( mask == string.Empty )
      {
        m_maskedTextProvider = this.CreateMaskedTextProvider( MaskedTextBox.NullMaskString );
        m_maskIsNull = true;
      }
      else
      {
        m_maskedTextProvider = this.CreateMaskedTextProvider( mask );
        m_maskIsNull = false;
      }

      if( ( !m_maskIsNull ) && ( preInitializedText != string.Empty ) )
      {
        bool success = m_maskedTextProvider.Add( preInitializedText );

        if( ( !success ) && ( !DesignerProperties.GetIsInDesignMode( this ) ) )
          throw new InvalidOperationException( "An attempt was made to apply a new mask that cannot be applied to the current text." );
      }
    }

    #endregion CONSTRUCTORS

    #region ISupportInitialize

    protected override void OnInitialized( EventArgs e )
    {
      this.InitializeMaskedTextProvider();

      this.SetIsMaskCompleted( m_maskedTextProvider.MaskCompleted );
      this.SetIsMaskFull( m_maskedTextProvider.MaskFull );

      base.OnInitialized( e );
    }

    #endregion ISupportInitialize

    #region AllowPromptAsInput Property

    public static readonly DependencyProperty AllowPromptAsInputProperty =
        DependencyProperty.Register( "AllowPromptAsInput", typeof( bool ), typeof( MaskedTextBox ),
      new UIPropertyMetadata(
      true,
      new PropertyChangedCallback( MaskedTextBox.AllowPromptAsInputPropertyChangedCallback ) ) );

    public bool AllowPromptAsInput
    {
      get
      {
        return ( bool )GetValue( AllowPromptAsInputProperty );
      }
      set
      {
        SetValue( AllowPromptAsInputProperty, value );
      }
    }

    private static void AllowPromptAsInputPropertyChangedCallback( object sender, DependencyPropertyChangedEventArgs e )
    {
      MaskedTextBox maskedTextBox = sender as MaskedTextBox;

      if( !maskedTextBox.IsInitialized )
        return;

      if( maskedTextBox.m_maskIsNull )
        return;

      maskedTextBox.m_maskedTextProvider = maskedTextBox.CreateMaskedTextProvider( maskedTextBox.Mask );
    }

    #endregion AllowPromptAsInput Property

    #region ClipboardMaskFormat Property

    public MaskFormat ClipboardMaskFormat
    {
      get
      {
        return ( MaskFormat )GetValue( ClipboardMaskFormatProperty );
      }
      set
      {
        SetValue( ClipboardMaskFormatProperty, value );
      }
    }

    public static readonly DependencyProperty ClipboardMaskFormatProperty =
        DependencyProperty.Register( "ClipboardMaskFormat", typeof( MaskFormat ), typeof( MaskedTextBox ),
      new UIPropertyMetadata( MaskFormat.IncludeLiterals ) );

    #endregion ClipboardMaskFormat Property

    #region HidePromptOnLeave Property

    public bool HidePromptOnLeave
    {
      get
      {
        return ( bool )GetValue( HidePromptOnLeaveProperty );
      }
      set
      {
        SetValue( HidePromptOnLeaveProperty, value );
      }
    }

    public static readonly DependencyProperty HidePromptOnLeaveProperty =
        DependencyProperty.Register( "HidePromptOnLeave", typeof( bool ), typeof( MaskedTextBox ), new UIPropertyMetadata( false ) );

    #endregion HidePromptOnLeave Property

    #region IncludeLiteralsInValue Property

    public bool IncludeLiteralsInValue
    {
      get
      {
        return ( bool )GetValue( IncludeLiteralsInValueProperty );
      }
      set
      {
        SetValue( IncludeLiteralsInValueProperty, value );
      }
    }

    public static readonly DependencyProperty IncludeLiteralsInValueProperty =
        DependencyProperty.Register( "IncludeLiteralsInValue", typeof( bool ), typeof( MaskedTextBox ),
      new UIPropertyMetadata(
      true,
      new PropertyChangedCallback( MaskedTextBox.InlcudeLiteralsInValuePropertyChangedCallback ) ) );

    private static void InlcudeLiteralsInValuePropertyChangedCallback( object sender, DependencyPropertyChangedEventArgs e )
    {
      MaskedTextBox maskedTextBox = sender as MaskedTextBox;

      if( !maskedTextBox.IsInitialized )
        return;

      maskedTextBox.RefreshConversionHelpers();
      maskedTextBox.RefreshValue();
    }

    #endregion IncludeLiteralsInValue Property

    #region IncludePromptInValue Property

    public bool IncludePromptInValue
    {
      get
      {
        return ( bool )GetValue( IncludePromptInValueProperty );
      }
      set
      {
        SetValue( IncludePromptInValueProperty, value );
      }
    }

    public static readonly DependencyProperty IncludePromptInValueProperty =
        DependencyProperty.Register( "IncludePromptInValue", typeof( bool ), typeof( MaskedTextBox ),
      new UIPropertyMetadata(
      false,
      new PropertyChangedCallback( MaskedTextBox.IncludePromptInValuePropertyChangedCallback ) ) );

    private static void IncludePromptInValuePropertyChangedCallback( object sender, DependencyPropertyChangedEventArgs e )
    {
      MaskedTextBox maskedTextBox = sender as MaskedTextBox;

      if( !maskedTextBox.IsInitialized )
        return;

      maskedTextBox.RefreshValue();
    }

    #endregion IncludePromptInValue Property

    #region InsertKeyMode Property

    public InsertKeyMode InsertKeyMode
    {
      get
      {
        return ( InsertKeyMode )GetValue( InsertKeyModeProperty );
      }
      set
      {
        SetValue( InsertKeyModeProperty, value );
      }
    }

    public static readonly DependencyProperty InsertKeyModeProperty =
        DependencyProperty.Register( "InsertKeyMode", typeof( InsertKeyMode ), typeof( MaskedTextBox ), new UIPropertyMetadata( InsertKeyMode.Default ) );

    #endregion InsertKeyMode Property

    #region IsMaskCompleted Read-Only Property

    private static readonly DependencyPropertyKey IsMaskCompletedPropertyKey =
        DependencyProperty.RegisterReadOnly( "IsMaskCompleted", typeof( bool ), typeof( MaskedTextBox ), new PropertyMetadata( false ) );

    public static readonly DependencyProperty IsMaskCompletedProperty = MaskedTextBox.IsMaskCompletedPropertyKey.DependencyProperty;


    public bool IsMaskCompleted
    {
      get
      {
        return ( bool )this.GetValue( MaskedTextBox.IsMaskCompletedProperty );
      }
    }

    private void SetIsMaskCompleted( bool value )
    {
      this.SetValue( MaskedTextBox.IsMaskCompletedPropertyKey, value );
    }

    #endregion IsMaskCompleted Read-Only Property

    #region IsMaskFull Read-Only Property

    private static readonly DependencyPropertyKey IsMaskFullPropertyKey =
        DependencyProperty.RegisterReadOnly( "IsMaskFull", typeof( bool ), typeof( MaskedTextBox ), new PropertyMetadata( false ) );

    public static readonly DependencyProperty IsMaskFullProperty = MaskedTextBox.IsMaskFullPropertyKey.DependencyProperty;

    public bool IsMaskFull
    {
      get
      {
        return ( bool )this.GetValue( MaskedTextBox.IsMaskFullProperty );
      }
    }

    private void SetIsMaskFull( bool value )
    {
      this.SetValue( MaskedTextBox.IsMaskFullPropertyKey, value );
    }

    #endregion IsMaskFull Read-Only Property

    #region Mask Property

    public static readonly DependencyProperty MaskProperty =
        DependencyProperty.Register( "Mask", typeof( string ), typeof( MaskedTextBox ),
      new UIPropertyMetadata(
      string.Empty,
      new PropertyChangedCallback( MaskedTextBox.MaskPropertyChangedCallback ),
      new CoerceValueCallback( MaskedTextBox.MaskCoerceValueCallback ) ) );

    public string Mask
    {
      get
      {
        return ( string )this.GetValue( MaskedTextBox.MaskProperty );
      }
      set
      {
        this.SetValue( MaskedTextBox.MaskProperty, value );
      }
    }

    [System.Diagnostics.CodeAnalysis.SuppressMessage( "Microsoft.Usage", "CA2208:InstantiateArgumentExceptionsCorrectly" )]
    private static object MaskCoerceValueCallback( DependencyObject sender, object value )
    {
      if( value == null )
        value = string.Empty;

      if( value.Equals( string.Empty ) )
        return value;

      // Validate the text against the would be new Mask.

      MaskedTextBox maskedTextBox = sender as MaskedTextBox;

      if( !maskedTextBox.IsInitialized )
        return value;

      bool valid;

      try
      {
        MaskedTextProvider provider = maskedTextBox.CreateMaskedTextProvider( ( string )value );

        string rawText = MaskedTextBox.GetRawText( maskedTextBox.m_maskedTextProvider );

        valid = provider.VerifyString( rawText );
      }
      catch( Exception exception )
      {
        throw new InvalidOperationException( "An error occured while testing the current text against the new mask.", exception );
      }

      if( !valid )
        throw new ArgumentException( "The mask cannot be applied to the current text.", "Mask" );

      return value;
    }

    [System.Diagnostics.CodeAnalysis.SuppressMessage( "Microsoft.Performance", "CA1820:TestForEmptyStringsUsingStringLength" )]
    private static void MaskPropertyChangedCallback( DependencyObject sender, DependencyPropertyChangedEventArgs e )
    {
      MaskedTextBox maskedTextBox = sender as MaskedTextBox;

      if( !maskedTextBox.IsInitialized )
        return;

      MaskedTextProvider provider = null;

      string mask = ( string )e.NewValue;

      if( mask == string.Empty )
      {
        provider = maskedTextBox.CreateMaskedTextProvider( MaskedTextBox.NullMaskString );
        maskedTextBox.m_maskIsNull = true;
        maskedTextBox.Text = "";
      }
      else
      {
        provider = maskedTextBox.CreateMaskedTextProvider( mask );
        maskedTextBox.m_maskIsNull = false;
      }

      maskedTextBox.m_maskedTextProvider = provider;

      maskedTextBox.RefreshConversionHelpers();

      if( maskedTextBox.ValueDataType != null )
      {
        string textFromValue = maskedTextBox.GetTextFromValue( maskedTextBox.Value );
        maskedTextBox.m_maskedTextProvider.Set( textFromValue );
      }

      maskedTextBox.RefreshCurrentText( true );
    }

    #endregion Mask Property

    #region MaskedTextProvider Property

    public MaskedTextProvider MaskedTextProvider
    {
      get
      {
        if( !m_maskIsNull )
          return m_maskedTextProvider.Clone() as MaskedTextProvider;

        return null;
      }
    }

    #endregion MaskedTextProvider Property

    #region PromptChar Property

    public static readonly DependencyProperty PromptCharProperty =
        DependencyProperty.Register( "PromptChar", typeof( char ), typeof( MaskedTextBox ),
      new UIPropertyMetadata(
      '_',
      new PropertyChangedCallback( MaskedTextBox.PromptCharPropertyChangedCallback ),
      new CoerceValueCallback( MaskedTextBox.PromptCharCoerceValueCallback ) ) );

    public char PromptChar
    {
      get
      {
        return ( char )this.GetValue( MaskedTextBox.PromptCharProperty );
      }
      set
      {
        this.SetValue( MaskedTextBox.PromptCharProperty, value );
      }
    }

    private static object PromptCharCoerceValueCallback( object sender, object value )
    {
      MaskedTextBox maskedTextBox = sender as MaskedTextBox;

      if( !maskedTextBox.IsInitialized )
        return value;

      MaskedTextProvider provider = maskedTextBox.m_maskedTextProvider.Clone() as MaskedTextProvider;

      try
      {
        provider.PromptChar = ( char )value;
      }
      catch( Exception exception )
      {
        throw new ArgumentException( "The prompt character is invalid.", exception );
      }

      return value;
    }

    private static void PromptCharPropertyChangedCallback( object sender, DependencyPropertyChangedEventArgs e )
    {
      MaskedTextBox maskedTextBox = sender as MaskedTextBox;

      if( !maskedTextBox.IsInitialized )
        return;

      if( maskedTextBox.m_maskIsNull )
        return;

      maskedTextBox.m_maskedTextProvider.PromptChar = ( char )e.NewValue;

      maskedTextBox.RefreshCurrentText( true );
    }

    #endregion PromptChar Property

    #region RejectInputOnFirstFailure Property

    public bool RejectInputOnFirstFailure
    {
      get
      {
        return ( bool )GetValue( RejectInputOnFirstFailureProperty );
      }
      set
      {
        SetValue( RejectInputOnFirstFailureProperty, value );
      }
    }

    public static readonly DependencyProperty RejectInputOnFirstFailureProperty =
        DependencyProperty.Register( "RejectInputOnFirstFailure", typeof( bool ), typeof( MaskedTextBox ), new UIPropertyMetadata( true ) );

    #endregion RejectInputOnFirstFailure Property

    #region ResetOnPrompt Property

    public bool ResetOnPrompt
    {
      get
      {
        return ( bool )GetValue( ResetOnPromptProperty );
      }
      set
      {
        SetValue( ResetOnPromptProperty, value );
      }
    }

    public static readonly DependencyProperty ResetOnPromptProperty =
        DependencyProperty.Register( "ResetOnPrompt", typeof( bool ), typeof( MaskedTextBox ),
      new UIPropertyMetadata(
      true,
      new PropertyChangedCallback( MaskedTextBox.ResetOnPromptPropertyChangedCallback ) ) );

    private static void ResetOnPromptPropertyChangedCallback( object sender, DependencyPropertyChangedEventArgs e )
    {
      MaskedTextBox maskedTextBox = sender as MaskedTextBox;

      if( !maskedTextBox.IsInitialized )
        return;

      if( maskedTextBox.m_maskIsNull )
        return;

      maskedTextBox.m_maskedTextProvider.ResetOnPrompt = ( bool )e.NewValue;
    }

    #endregion ResetOnPrompt Property

    #region ResetOnSpace Property

    public bool ResetOnSpace
    {
      get
      {
        return ( bool )GetValue( ResetOnSpaceProperty );
      }
      set
      {
        SetValue( ResetOnSpaceProperty, value );
      }
    }

    public static readonly DependencyProperty ResetOnSpaceProperty =
        DependencyProperty.Register( "ResetOnSpace", typeof( bool ), typeof( MaskedTextBox ),
      new UIPropertyMetadata(
      true,
      new PropertyChangedCallback( MaskedTextBox.ResetOnSpacePropertyChangedCallback ) ) );

    private static void ResetOnSpacePropertyChangedCallback( object sender, DependencyPropertyChangedEventArgs e )
    {
      MaskedTextBox maskedTextBox = sender as MaskedTextBox;

      if( !maskedTextBox.IsInitialized )
        return;

      if( maskedTextBox.m_maskIsNull )
        return;

      maskedTextBox.m_maskedTextProvider.ResetOnSpace = ( bool )e.NewValue;
    }

    #endregion ResetOnSpace Property

    #region RestrictToAscii Property

    public bool RestrictToAscii
    {
      get
      {
        return ( bool )GetValue( RestrictToAsciiProperty );
      }
      set
      {
        SetValue( RestrictToAsciiProperty, value );
      }
    }

    public static readonly DependencyProperty RestrictToAsciiProperty =
        DependencyProperty.Register( "RestrictToAscii", typeof( bool ), typeof( MaskedTextBox ),
      new UIPropertyMetadata(
      false,
      new PropertyChangedCallback( MaskedTextBox.RestrictToAsciiPropertyChangedCallback ),
      new CoerceValueCallback( MaskedTextBox.RestrictToAsciiCoerceValueCallback ) ) );

    [System.Diagnostics.CodeAnalysis.SuppressMessage( "Microsoft.Usage", "CA2208:InstantiateArgumentExceptionsCorrectly" )]
    private static object RestrictToAsciiCoerceValueCallback( object sender, object value )
    {
      MaskedTextBox maskedTextBox = sender as MaskedTextBox;

      if( !maskedTextBox.IsInitialized )
        return value;

      if( maskedTextBox.m_maskIsNull )
        return value;

      bool restrictToAscii = ( bool )value;

      if( !restrictToAscii )
        return value;

      // Validate the text to make sure that it is only made of Ascii characters.

      MaskedTextProvider provider = maskedTextBox.CreateMaskedTextProvider(
        maskedTextBox.Mask,
        maskedTextBox.GetCultureInfo(),
        maskedTextBox.AllowPromptAsInput,
        maskedTextBox.PromptChar,
        MaskedTextBox.DefaultPasswordChar,
        restrictToAscii );

      if( !provider.VerifyString( maskedTextBox.Text ) )
        throw new ArgumentException( "The current text cannot be restricted to ASCII characters. The RestrictToAscii property is set to true.", "RestrictToAscii" );

      return restrictToAscii;
    }

    private static void RestrictToAsciiPropertyChangedCallback( object sender, DependencyPropertyChangedEventArgs e )
    {
      MaskedTextBox maskedTextBox = sender as MaskedTextBox;

      if( !maskedTextBox.IsInitialized )
        return;

      if( maskedTextBox.m_maskIsNull )
        return;

      maskedTextBox.m_maskedTextProvider = maskedTextBox.CreateMaskedTextProvider( maskedTextBox.Mask );

      maskedTextBox.RefreshCurrentText( true );
    }

    #endregion RestrictToAscii Property

    #region SkipLiterals Property

    public bool SkipLiterals
    {
      get
      {
        return ( bool )GetValue( SkipLiteralsProperty );
      }
      set
      {
        SetValue( SkipLiteralsProperty, value );
      }
    }

    public static readonly DependencyProperty SkipLiteralsProperty =
        DependencyProperty.Register( "SkipLiterals", typeof( bool ), typeof( MaskedTextBox ),
      new UIPropertyMetadata(
      true,
      new PropertyChangedCallback( MaskedTextBox.SkipLiteralsPropertyChangedCallback ) ) );

    private static void SkipLiteralsPropertyChangedCallback( object sender, DependencyPropertyChangedEventArgs e )
    {
      MaskedTextBox maskedTextBox = sender as MaskedTextBox;

      if( !maskedTextBox.IsInitialized )
        return;

      if( maskedTextBox.m_maskIsNull )
        return;

      maskedTextBox.m_maskedTextProvider.SkipLiterals = ( bool )e.NewValue;
    }

    #endregion SkipLiterals Property

    #region Text Property

    private static object TextCoerceValueCallback( DependencyObject sender, object value )
    {
      MaskedTextBox maskedTextBox = sender as MaskedTextBox;

      if( !maskedTextBox.IsInitialized )
        return DependencyProperty.UnsetValue;

      if( maskedTextBox.IsInIMEComposition )
      {
        // In IME Composition.  We must return an uncoerced value or else the IME decorator won't disappear after text input.
        return value;
      }

      if( value == null )
        value = string.Empty;

      if( ( maskedTextBox.IsForcingText ) || ( maskedTextBox.m_maskIsNull ) )
        return value;

      // Only direct affectation to the Text property or binding of the Text property should
      // come through here.  All other cases should pre-validate the text and affect it through the ForceText method.
      string text = maskedTextBox.ValidateText( ( string )value );

      return text;
    }

    private string ValidateText( string text )
    {
      string coercedText = text;

      if( this.RejectInputOnFirstFailure )
      {
        MaskedTextProvider provider = m_maskedTextProvider.Clone() as MaskedTextProvider;

        int notUsed;
        MaskedTextResultHint hint;

        if( provider.Set( text, out notUsed, out hint ) )
        {
          coercedText = this.GetFormattedString( provider );
        }
        else
        {
          // Coerce the text to remain the same.
          coercedText = this.GetFormattedString( m_maskedTextProvider );

          // The TextPropertyChangedCallback won't be called.
          // Therefore, we must sync the maskedTextProvider.
          m_maskedTextProvider.Set( coercedText );
        }
      }
      else
      {
        MaskedTextProvider provider = ( MaskedTextProvider )m_maskedTextProvider.Clone();

        int caretIndex;

        if( this.CanReplace( provider, text, 0, m_maskedTextProvider.Length, this.RejectInputOnFirstFailure, out caretIndex ) )
        {
          coercedText = this.GetFormattedString( provider );
        }
        else
        {
          // Coerce the text to remain the same.
          coercedText = this.GetFormattedString( m_maskedTextProvider );

          // The TextPropertyChangedCallback won't be called.
          // Therefore, we must sync the maskedTextProvider.
          m_maskedTextProvider.Set( coercedText );
        }
      }

      return coercedText;
    }

    protected override void OnTextChanged( TextChangedEventArgs e )
    {
      if( !m_maskIsNull )
      {
        if( ( this.IsInValueChanged ) || ( !this.IsForcingText ) )
        {
          string newText = this.Text;

          if( m_maskIsNull )
          {
            this.CaretIndex = newText.Length;
          }
          else
          {
            m_maskedTextProvider.Set( newText );

            int caretIndex = m_maskedTextProvider.FindUnassignedEditPositionFrom( 0, true );

            if( caretIndex == -1 )
              caretIndex = m_maskedTextProvider.Length;

            this.CaretIndex = caretIndex;
          }
        }
      }

      // m_maskedTextProvider can be null in the designer. With WPF 3.5 SP1, sometimes, 
      // TextChanged will be triggered before OnInitialized is called.
      if( m_maskedTextProvider != null )
      {
        this.SetIsMaskCompleted( m_maskedTextProvider.MaskCompleted );
        this.SetIsMaskFull( m_maskedTextProvider.MaskFull );
      }

      base.OnTextChanged( e );
    }

    #endregion Text Property


    #region COMMANDS

    private void OnPreviewCanExecuteCommands( object sender, CanExecuteRoutedEventArgs e )
    {
      if( m_maskIsNull )
        return;

      RoutedUICommand routedUICommand = e.Command as RoutedUICommand;

      if( ( routedUICommand != null )
        && ( ( routedUICommand.Name == "Space" ) || ( routedUICommand.Name == "ShiftSpace" ) ) )
      {
        if( this.IsReadOnly )
        {
          e.CanExecute = false;
        }
        else
        {
          MaskedTextProvider provider = ( MaskedTextProvider )m_maskedTextProvider.Clone();
          int caretIndex;
          e.CanExecute = this.CanReplace( provider, " ", this.SelectionStart, this.SelectionLength, this.RejectInputOnFirstFailure, out caretIndex );
        }

        e.Handled = true;
      }
      else if( ( e.Command == ApplicationCommands.Undo ) || ( e.Command == ApplicationCommands.Redo ) )
      {
        e.CanExecute = false;
        e.Handled = true;
      }
    }

    private void OnPreviewExecutedCommands( object sender, ExecutedRoutedEventArgs e )
    {
      if( m_maskIsNull )
        return;

      if( e.Command == EditingCommands.Delete )
      {
        e.Handled = true;
        this.Delete( this.SelectionStart, this.SelectionLength, true );
      }
      else if( e.Command == EditingCommands.DeleteNextWord )
      {
        e.Handled = true;
        EditingCommands.SelectRightByWord.Execute( null, this as IInputElement );
        this.Delete( this.SelectionStart, this.SelectionLength, true );
      }
      else if( e.Command == EditingCommands.DeletePreviousWord )
      {
        e.Handled = true;
        EditingCommands.SelectLeftByWord.Execute( null, this as IInputElement );
        this.Delete( this.SelectionStart, this.SelectionLength, false );
      }
      else if( e.Command == EditingCommands.Backspace )
      {
        e.Handled = true;
        this.Delete( this.SelectionStart, this.SelectionLength, false );
      }
      else if( e.Command == ApplicationCommands.Cut )
      {
        e.Handled = true;

        if( ApplicationCommands.Copy.CanExecute( null, this as IInputElement ) )
          ApplicationCommands.Copy.Execute( null, this as IInputElement );

        this.Delete( this.SelectionStart, this.SelectionLength, true );
      }
      else if( e.Command == ApplicationCommands.Copy )
      {
        e.Handled = true;
        this.ExecuteCopy();
      }
      else if( e.Command == ApplicationCommands.Paste )
      {
        e.Handled = true;

        string clipboardContent = ( string )Clipboard.GetDataObject().GetData( "System.String" );
        this.Replace( clipboardContent, this.SelectionStart, this.SelectionLength );
      }
      else
      {
        RoutedUICommand routedUICommand = e.Command as RoutedUICommand;

        if( ( routedUICommand != null )
          && ( ( routedUICommand.Name == "Space" ) || ( routedUICommand.Name == "ShiftSpace" ) ) )
        {
          e.Handled = true;
          this.ProcessTextInput( " " );
        }
      }
    }

    private void CanExecuteDelete( object sender, CanExecuteRoutedEventArgs e )
    {
      if( m_maskIsNull )
        return;

      e.CanExecute = this.CanDelete( this.SelectionStart, this.SelectionLength, true, this.MaskedTextProvider.Clone() as MaskedTextProvider );
      e.Handled = true;

      if( ( !e.CanExecute ) && ( this.BeepOnError ) )
        System.Media.SystemSounds.Beep.Play();
    }

    private void CanExecuteDeletePreviousWord( object sender, CanExecuteRoutedEventArgs e )
    {
      if( m_maskIsNull )
        return;

      bool canDeletePreviousWord = ( !this.IsReadOnly ) && ( EditingCommands.SelectLeftByWord.CanExecute( null, this as IInputElement ) );

      if( canDeletePreviousWord )
      {
        int cachedSelectionStart = this.SelectionStart;
        int cachedSelectionLength = this.SelectionLength;

        EditingCommands.SelectLeftByWord.Execute( null, this as IInputElement );

        canDeletePreviousWord = this.CanDelete( this.SelectionStart, this.SelectionLength, false, this.MaskedTextProvider.Clone() as MaskedTextProvider );

        if( !canDeletePreviousWord )
        {
          this.SelectionStart = cachedSelectionStart;
          this.SelectionLength = cachedSelectionLength;
        }
      }

      e.CanExecute = canDeletePreviousWord;
      e.Handled = true;

      if( ( !e.CanExecute ) && ( this.BeepOnError ) )
        System.Media.SystemSounds.Beep.Play();
    }

    private void CanExecuteDeleteNextWord( object sender, CanExecuteRoutedEventArgs e )
    {
      if( m_maskIsNull )
        return;

      bool canDeleteNextWord = ( !this.IsReadOnly ) && ( EditingCommands.SelectRightByWord.CanExecute( null, this as IInputElement ) );

      if( canDeleteNextWord )
      {
        int cachedSelectionStart = this.SelectionStart;
        int cachedSelectionLength = this.SelectionLength;

        EditingCommands.SelectRightByWord.Execute( null, this as IInputElement );

        canDeleteNextWord = this.CanDelete( this.SelectionStart, this.SelectionLength, true, this.MaskedTextProvider.Clone() as MaskedTextProvider );

        if( !canDeleteNextWord )
        {
          this.SelectionStart = cachedSelectionStart;
          this.SelectionLength = cachedSelectionLength;
        }
      }

      e.CanExecute = canDeleteNextWord;
      e.Handled = true;

      if( ( !e.CanExecute ) && ( this.BeepOnError ) )
        System.Media.SystemSounds.Beep.Play();
    }

    private void CanExecuteBackspace( object sender, CanExecuteRoutedEventArgs e )
    {
      if( m_maskIsNull )
        return;

      e.CanExecute = this.CanDelete( this.SelectionStart, this.SelectionLength, false, this.MaskedTextProvider.Clone() as MaskedTextProvider );
      e.Handled = true;

      if( ( !e.CanExecute ) && ( this.BeepOnError ) )
        System.Media.SystemSounds.Beep.Play();
    }

    private void CanExecuteCut( object sender, CanExecuteRoutedEventArgs e )
    {
      if( m_maskIsNull )
        return;

      bool canCut = ( !this.IsReadOnly ) && ( this.SelectionLength > 0 );

      if( canCut )
      {
        int endPosition = ( this.SelectionLength > 0 ) ? ( ( this.SelectionStart + this.SelectionLength ) - 1 ) : this.SelectionStart;

        MaskedTextProvider provider = m_maskedTextProvider.Clone() as MaskedTextProvider;

        canCut = provider.RemoveAt( this.SelectionStart, endPosition );
      }

      e.CanExecute = canCut;
      e.Handled = true;

      if( ( !canCut ) && ( this.BeepOnError ) )
        System.Media.SystemSounds.Beep.Play();
    }

    private void CanExecutePaste( object sender, CanExecuteRoutedEventArgs e )
    {
      if( m_maskIsNull )
        return;

      bool canPaste = false;

      if( !this.IsReadOnly )
      {
        string clipboardContent = string.Empty;

        try
        {
          clipboardContent = ( string )Clipboard.GetDataObject().GetData( "System.String" );

          if( clipboardContent != null )
          {
            MaskedTextProvider provider = ( MaskedTextProvider )m_maskedTextProvider.Clone();
            int caretIndex;
            canPaste = this.CanReplace( provider, clipboardContent, this.SelectionStart, this.SelectionLength, this.RejectInputOnFirstFailure, out caretIndex );
          }
        }
        catch
        {
        }
      }

      e.CanExecute = canPaste;
      e.Handled = true;

      if( ( !e.CanExecute ) && ( this.BeepOnError ) )
        System.Media.SystemSounds.Beep.Play();
    }

    private void CanExecuteCopy( object sender, CanExecuteRoutedEventArgs e )
    {
      if( m_maskIsNull )
        return;

      e.CanExecute = !m_maskedTextProvider.IsPassword;
      e.Handled = true;

      if( ( !e.CanExecute ) && ( this.BeepOnError ) )
        System.Media.SystemSounds.Beep.Play();
    }

    private void ExecuteCopy()
    {
      string selectedText = this.GetSelectedText();
      try
      {
        new UIPermission( UIPermissionClipboard.AllClipboard ).Demand();

        if( selectedText.Length == 0 )
        {
          Clipboard.Clear();
        }
        else
        {
          Clipboard.SetText( selectedText );
        }
      }
      catch( SecurityException )
      {
      }
    }

    private void ToggleInsertExecutedCallback( object sender, ExecutedRoutedEventArgs e )
    {
      m_insertToggled = !m_insertToggled;
    }

    #endregion COMMANDS

    #region DRAG DROP

    private void PreviewQueryContinueDragCallback( object sender, QueryContinueDragEventArgs e )
    {
      if( m_maskIsNull )
        return;

      e.Action = DragAction.Cancel;
      e.Handled = true;
    }

    protected override void OnDragEnter( DragEventArgs e )
    {
      if( !m_maskIsNull )
      {
        e.Effects = DragDropEffects.None;
        e.Handled = true;
      }

      base.OnDragEnter( e );
    }

    protected override void OnDragOver( DragEventArgs e )
    {
      if( !m_maskIsNull )
      {
        e.Effects = DragDropEffects.None;
        e.Handled = true;
      }

      base.OnDragOver( e );
    }

    #endregion DRAG DROP


    #region VALUE FROM TEXT

    protected override bool QueryValueFromTextCore( string text, out object value )
    {
      Type valueDataType = this.ValueDataType;

      if( valueDataType != null )
      {
        if( ( m_unhandledLiteralsPositions != null )
          && ( m_unhandledLiteralsPositions.Count > 0 ) )
        {
          text = m_maskedTextProvider.ToString( false, false, true, 0, m_maskedTextProvider.Length );

          for( int i = m_unhandledLiteralsPositions.Count - 1; i >= 0; i-- )
          {
            text = text.Remove( m_unhandledLiteralsPositions[ i ], 1 );
          }
        }
      }

      return base.QueryValueFromTextCore( text, out value );
    }

    #endregion VALUE FROM TEXT

    #region TEXT FROM VALUE

    protected override string QueryTextFromValueCore( object value )
    {
      if( ( m_valueToStringMethodInfo != null ) && ( value != null ) )
      {
        try
        {
          string text = ( string )m_valueToStringMethodInfo.Invoke( value, new object[] { m_formatSpecifier, this.GetActiveFormatProvider() } );
          return text;
        }
        catch
        {
        }
      }

      return base.QueryTextFromValueCore( value );
    }

    #endregion TEXT FROM VALUE


    #region PROTECTED METHODS

    protected virtual char[] GetMaskCharacters()
    {
      return MaskedTextBox.MaskChars;
    }

    private MaskedTextProvider CreateMaskedTextProvider( string mask )
    {
      return this.CreateMaskedTextProvider(
        mask,
        this.GetCultureInfo(),
        this.AllowPromptAsInput,
        this.PromptChar,
        MaskedTextBox.DefaultPasswordChar,
        this.RestrictToAscii );
    }

    protected virtual MaskedTextProvider CreateMaskedTextProvider(
      string mask,
      CultureInfo cultureInfo,
      bool allowPromptAsInput,
      char promptChar,
      char passwordChar,
      bool restrictToAscii )
    {
      MaskedTextProvider provider = new MaskedTextProvider(
        mask,
        cultureInfo,
        allowPromptAsInput,
        promptChar,
        passwordChar,
        restrictToAscii );

      provider.ResetOnPrompt = this.ResetOnPrompt;
      provider.ResetOnSpace = this.ResetOnSpace;
      provider.SkipLiterals = this.SkipLiterals;

      provider.IncludeLiterals = true;
      provider.IncludePrompt = true;

      provider.IsPassword = false;

      return provider;
    }

    internal override void OnIMECompositionEnded( CachedTextInfo cachedTextInfo )
    {
      // End of IME Composition.  Restore the critical infos.
      this.ForceText( cachedTextInfo.Text, false );
      this.CaretIndex = cachedTextInfo.CaretIndex;
      this.SelectionStart = cachedTextInfo.SelectionStart;
      this.SelectionLength = cachedTextInfo.SelectionLength;
    }

    protected override void OnTextInput( System.Windows.Input.TextCompositionEventArgs e )
    {
      if( this.IsInIMEComposition )
        this.EndIMEComposition();

      if( ( m_maskIsNull ) || ( m_maskedTextProvider == null ) || ( this.IsReadOnly ) )
      {
        base.OnTextInput( e );
        return;
      }

      e.Handled = true;

      if( this.CharacterCasing == CharacterCasing.Upper )
      {
        this.ProcessTextInput( e.Text.ToUpper() );
      }
      else if( this.CharacterCasing == CharacterCasing.Lower )
      {
        this.ProcessTextInput( e.Text.ToLower() );
      }
      else
      {
        this.ProcessTextInput( e.Text );
      }

      base.OnTextInput( e );
    }

    private void ProcessTextInput( string text )
    {
      if( text.Length == 1 )
      {
        string textOutput = this.MaskedTextOutput;

        int caretIndex;
        if( this.PlaceChar( text[ 0 ], this.SelectionStart, this.SelectionLength, this.IsOverwriteMode, out caretIndex ) )
        {
          if( this.MaskedTextOutput != textOutput )
            this.RefreshCurrentText( false );

          this.SelectionStart = caretIndex + 1;
        }
        else
        {
          if( this.BeepOnError )
            System.Media.SystemSounds.Beep.Play();
        }

        if( this.SelectionLength > 0 )
          this.SelectionLength = 0;
      }
      else
      {
        this.Replace( text, this.SelectionStart, this.SelectionLength );
      }
    }

    protected override void ValidateValue( object value )
    {
      base.ValidateValue( value );

      // Validate if it fits in the mask
      if( !m_maskIsNull )
      {
        string representation = this.GetTextFromValue( value );

        MaskedTextProvider provider = m_maskedTextProvider.Clone() as MaskedTextProvider;

        if( !provider.VerifyString( representation ) )
          throw new ArgumentException( "The value representation '" + representation + "' does not match the mask.", "value" );
      }
    }

    #endregion PROTECTED METHODS


    #region INTERNAL PROPERTIES

    internal bool IsForcingMask
    {
      get
      {
        return m_forcingMask;
      }
    }

    internal string FormatSpecifier
    {
      get
      {
        return m_formatSpecifier;
      }
      set
      {
        m_formatSpecifier = value;
      }
    }

    internal override bool IsTextReadyToBeParsed
    {
      get
      {
        return this.IsMaskCompleted;
      }
    }

    internal override bool GetIsEditTextEmpty()
    {
      return ( this.MaskedTextProvider.AssignedEditPositionCount == 0 );
    }

    #endregion INTERNAL PROPERTIES

    #region INTERNAL METHODS

    internal override string GetCurrentText()
    {
      if( m_maskIsNull )
        return base.GetCurrentText();

      string displayText = this.GetFormattedString( m_maskedTextProvider );

      return displayText;
    }

    internal override string GetParsableText()
    {
      if( m_maskIsNull )
        return base.GetParsableText();

      bool includePrompt = false;
      bool includeLiterals = true;

      if( this.ValueDataType == typeof( string ) )
      {
        includePrompt = this.IncludePromptInValue;
        includeLiterals = this.IncludeLiteralsInValue;
      }

      return m_maskedTextProvider
        .ToString( false, includePrompt, includeLiterals, 0, m_maskedTextProvider.Length );
    }

    internal override void OnFormatProviderChanged()
    {
      MaskedTextProvider provider = new MaskedTextProvider( this.Mask );

      m_maskedTextProvider = provider;

      this.RefreshConversionHelpers();
      this.RefreshCurrentText( true );

      base.OnFormatProviderChanged();
    }

    internal override void RefreshConversionHelpers()
    {
      Type type = this.ValueDataType;

      if( ( type == null ) || ( !this.IsNumericValueDataType ) )
      {
        m_formatSpecifier = null;
        m_valueToStringMethodInfo = null;
        m_unhandledLiteralsPositions = null;
        return;
      }

      m_valueToStringMethodInfo = type.GetMethod( "ToString", new Type[] { typeof( string ), typeof( IFormatProvider ) } );

      string mask = m_maskedTextProvider.Mask;
      IFormatProvider activeFormatProvider = this.GetActiveFormatProvider();

      char[] maskChars = this.GetMaskCharacters();

      List<int> unhandledLiteralsPositions;

      m_formatSpecifier = MaskedTextBox.GetFormatSpecifierFromMask(
        mask,
        maskChars,
        activeFormatProvider,
        this.IncludeLiteralsInValue,
        out unhandledLiteralsPositions );

      NumberFormatInfo numberFormatInfo = activeFormatProvider.GetFormat( typeof( NumberFormatInfo ) ) as NumberFormatInfo;

      if( numberFormatInfo != null )
      {
        string negativeSign = numberFormatInfo.NegativeSign;

        if( m_formatSpecifier.Contains( negativeSign ) )
        {
          // We must make sure that the value data type is numeric since we are about to 
          // set the format specifier to its Positive,Negative,Zero format pattern.
          // If we do not do this, the negative symbol would double itself when IncludeLiteralsInValue
          // is set to True and a negative symbol is added to the mask as a literal.
          Debug.Assert( this.IsNumericValueDataType );

          m_formatSpecifier = m_formatSpecifier + ";" + m_formatSpecifier + ";" + m_formatSpecifier;
        }
        else
        {

        }
      }

      m_unhandledLiteralsPositions = unhandledLiteralsPositions;
    }

    internal void SetValueToStringMethodInfo( MethodInfo valueToStringMethodInfo )
    {
      m_valueToStringMethodInfo = valueToStringMethodInfo;
    }

    internal void ForceMask( string mask )
    {
      m_forcingMask = true;

      try
      {
        this.Mask = mask;
      }
      finally
      {
        m_forcingMask = false;
      }
    }

    #endregion INTERNAL METHODS

    #region PRIVATE PROPERTIES

    private bool IsOverwriteMode
    {
      get
      {
        if( !m_maskIsNull )
        {
          switch( this.InsertKeyMode )
          {
            case InsertKeyMode.Default:
              {
                return m_insertToggled;
              }

            case InsertKeyMode.Insert:
              {
                return false;
              }

            case InsertKeyMode.Overwrite:
              {
                return true;
              }
          }
        }

        return false;
      }
    }

    #endregion PRIVATE PROPERTIES

    #region PRIVATE METHODS

    private bool PlaceChar( char ch, int startPosition, int length, bool overwrite, out int caretIndex )
    {
      return this.PlaceChar( m_maskedTextProvider, ch, startPosition, length, overwrite, out caretIndex );
    }


    private bool PlaceChar( MaskedTextProvider provider, char ch, int startPosition, int length, bool overwrite, out int caretPosition )
    {
      if( this.ShouldQueryAutoCompleteMask( provider.Clone() as MaskedTextProvider, ch, startPosition ) )
      {
        AutoCompletingMaskEventArgs e = new AutoCompletingMaskEventArgs(
          m_maskedTextProvider.Clone() as MaskedTextProvider,
          startPosition,
          length,
          ch.ToString() );

        this.OnAutoCompletingMask( e );

        if( ( !e.Cancel ) && ( e.AutoCompleteStartPosition > -1 ) )
        {
          caretPosition = startPosition;

          // AutoComplete the block.
          for( int i = 0; i < e.AutoCompleteText.Length; i++ )
          {
            if( !this.PlaceCharCore( provider, e.AutoCompleteText[ i ], e.AutoCompleteStartPosition + i, 0, true, out caretPosition ) )
              return false;
          }

          caretPosition = e.AutoCompleteStartPosition + e.AutoCompleteText.Length;
          return true;
        }
      }

      return this.PlaceCharCore( provider, ch, startPosition, length, overwrite, out caretPosition );
    }

    private bool ShouldQueryAutoCompleteMask( MaskedTextProvider provider, char ch, int startPosition )
    {
      if( provider.IsEditPosition( startPosition ) )
      {
        int nextSeparatorIndex = provider.FindNonEditPositionFrom( startPosition, true );

        if( nextSeparatorIndex != -1 )
        {
          if( provider[ nextSeparatorIndex ].Equals( ch ) )
          {
            int previousSeparatorIndex = provider.FindNonEditPositionFrom( startPosition, false );

            if( provider.FindUnassignedEditPositionInRange( previousSeparatorIndex, nextSeparatorIndex, true ) != -1 )
            {
              return true;
            }
          }
        }
      }

      return false;
    }

    protected virtual void OnAutoCompletingMask( AutoCompletingMaskEventArgs e )
    {
      if( this.AutoCompletingMask != null )
        this.AutoCompletingMask( this, e );
    }

    public event EventHandler<AutoCompletingMaskEventArgs> AutoCompletingMask;


    private bool PlaceCharCore( MaskedTextProvider provider, char ch, int startPosition, int length, bool overwrite, out int caretPosition )
    {
      caretPosition = startPosition;

      if( startPosition < m_maskedTextProvider.Length )
      {
        MaskedTextResultHint notUsed;

        if( length > 0 )
        {
          int endPosition = ( startPosition + length ) - 1;
          return provider.Replace( ch, startPosition, endPosition, out caretPosition, out notUsed );
        }

        if( overwrite )
          return provider.Replace( ch, startPosition, out caretPosition, out notUsed );

        return provider.InsertAt( ch, startPosition, out caretPosition, out notUsed );
      }

      return false;
    }

    internal void Replace( string text, int startPosition, int selectionLength )
    {
      MaskedTextProvider provider = ( MaskedTextProvider )m_maskedTextProvider.Clone();
      int tentativeCaretIndex;

      if( this.CanReplace( provider, text, startPosition, selectionLength, this.RejectInputOnFirstFailure, out tentativeCaretIndex ) )
      {
        System.Diagnostics.Debug.WriteLine( "Replace caret index to: " + tentativeCaretIndex.ToString() );

        bool mustRefreshText = this.MaskedTextOutput != provider.ToString();
        m_maskedTextProvider = provider;

        if( mustRefreshText )
          this.RefreshCurrentText( false );

        this.CaretIndex = tentativeCaretIndex + 1;
      }
      else
      {
        if( this.BeepOnError )
          System.Media.SystemSounds.Beep.Play();
      }
    }

    internal virtual bool CanReplace( MaskedTextProvider provider, string text, int startPosition, int selectionLength, bool rejectInputOnFirstFailure, out int tentativeCaretIndex )
    {
      int endPosition = ( startPosition + selectionLength ) - 1;
      tentativeCaretIndex = -1;


      bool success = false;

      foreach( char ch in text )
      {
        if( !m_maskedTextProvider.VerifyEscapeChar( ch, startPosition ) )
        {
          int editPositionFrom = provider.FindEditPositionFrom( startPosition, true );

          if( editPositionFrom == MaskedTextProvider.InvalidIndex )
            break;

          startPosition = editPositionFrom;
        }

        int length = ( endPosition >= startPosition ) ? 1 : 0;
        bool overwrite = length > 0;

        if( this.PlaceChar( provider, ch, startPosition, length, overwrite, out tentativeCaretIndex ) )
        {
          // Only one successfully inserted character is enough to declare the replace operation successful.
          success = true;

          startPosition = tentativeCaretIndex + 1;
        }
        else if( rejectInputOnFirstFailure )
        {
          return false;
        }
      }

      if( ( selectionLength > 0 ) && ( startPosition <= endPosition ) )
      {

        // Erase the remaining of the assigned edit character.
        int notUsed;
        MaskedTextResultHint notUsedHint;
        if( !provider.RemoveAt( startPosition, endPosition, out notUsed, out notUsedHint ) )
          success = false;
      }

      return success;
    }

    private bool CanDelete( int startPosition, int selectionLength, bool deleteForward, MaskedTextProvider provider )
    {
      if( this.IsReadOnly )
        return false;


      if( selectionLength == 0 )
      {
        if( !deleteForward )
        {
          if( startPosition == 0 )
            return false;

          startPosition--;
        }
        else if( ( startPosition + selectionLength ) == provider.Length )
        {
          return false;
        }
      }

      MaskedTextResultHint notUsed;
      int tentativeCaretPosition = startPosition;

      int endPosition = ( selectionLength > 0 ) ? ( ( startPosition + selectionLength ) - 1 ) : startPosition;

      bool success = provider.RemoveAt( startPosition, endPosition, out tentativeCaretPosition, out notUsed );

      return success;
    }

    private void Delete( int startPosition, int selectionLength, bool deleteForward )
    {
      if( this.IsReadOnly )
        return;


      if( selectionLength == 0 )
      {
        if( !deleteForward )
        {
          if( startPosition == 0 )
            return;

          startPosition--;
        }
        else if( ( startPosition + selectionLength ) == m_maskedTextProvider.Length )
        {
          return;
        }
      }

      MaskedTextResultHint hint;
      int tentativeCaretPosition = startPosition;

      int endPosition = ( selectionLength > 0 ) ? ( ( startPosition + selectionLength ) - 1 ) : startPosition;

      string oldTextOutput = this.MaskedTextOutput;

      bool success = m_maskedTextProvider.RemoveAt( startPosition, endPosition, out tentativeCaretPosition, out hint );

      if( !success )
      {
        if( this.BeepOnError )
          System.Media.SystemSounds.Beep.Play();

        return;
      }

      if( this.MaskedTextOutput != oldTextOutput )
      {
        this.RefreshCurrentText( false );
      }
      else if( selectionLength > 0 )
      {
        tentativeCaretPosition = startPosition;
      }
      else if( hint == MaskedTextResultHint.NoEffect )
      {
        if( deleteForward )
        {
          tentativeCaretPosition = m_maskedTextProvider.FindEditPositionFrom( startPosition, true );
        }
        else
        {
          if( m_maskedTextProvider.FindAssignedEditPositionFrom( startPosition, true ) == MaskedTextProvider.InvalidIndex )
          {
            tentativeCaretPosition = m_maskedTextProvider.FindAssignedEditPositionFrom( startPosition, false );
          }
          else
          {
            tentativeCaretPosition = m_maskedTextProvider.FindEditPositionFrom( startPosition, false );
          }

          if( tentativeCaretPosition != MaskedTextProvider.InvalidIndex )
            tentativeCaretPosition++;
        }

        if( tentativeCaretPosition == MaskedTextProvider.InvalidIndex )
          tentativeCaretPosition = startPosition;
      }
      else if( !deleteForward )
      {
        tentativeCaretPosition = startPosition;
      }

      this.CaretIndex = tentativeCaretPosition;
    }

    private string MaskedTextOutput
    {
      get
      {
        System.Diagnostics.Debug.Assert( m_maskedTextProvider.EditPositionCount > 0 );

        return m_maskedTextProvider.ToString();
      }
    }

    private string GetRawText()
    {
      if( m_maskIsNull )
        return this.Text;

      return MaskedTextBox.GetRawText( m_maskedTextProvider );
    }

    private string GetFormattedString( MaskedTextProvider provider )
    {
      System.Diagnostics.Debug.Assert( provider.EditPositionCount > 0 );


      bool includePrompt = ( this.IsReadOnly ) ? false : ( !this.HidePromptOnLeave || this.IsFocused );

      string displayString = provider.ToString( false, includePrompt, true, 0, m_maskedTextProvider.Length );

      return displayString;
    }

    private string GetSelectedText()
    {
      System.Diagnostics.Debug.Assert( !m_maskIsNull );

      int selectionLength = this.SelectionLength;

      if( selectionLength == 0 )
        return string.Empty;

      bool includePrompt = ( this.ClipboardMaskFormat & MaskFormat.IncludePrompt ) != MaskFormat.ExcludePromptAndLiterals;
      bool includeLiterals = ( this.ClipboardMaskFormat & MaskFormat.IncludeLiterals ) != MaskFormat.ExcludePromptAndLiterals;

      return m_maskedTextProvider.ToString( true, includePrompt, includeLiterals, this.SelectionStart, selectionLength );
    }

    #endregion PRIVATE METHODS

    #region PRIVATE FIELDS

    private MaskedTextProvider m_maskedTextProvider; // = null;
    private bool m_insertToggled; // = false;
    private bool m_maskIsNull = true;
    private bool m_forcingMask; // = false;

    List<int> m_unhandledLiteralsPositions; // = null;
    private string m_formatSpecifier;
    private MethodInfo m_valueToStringMethodInfo; // = null;

    #endregion PRIVATE FIELDS
  }
}
