TextTreePropertyUndoUnit.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Framework / System / Windows / Documents / TextTreePropertyUndoUnit.cs / 1 / TextTreePropertyUndoUnit.cs
                        

                        
                            //---------------------------------------------------------------------------- 
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved.
//  
//
// 
// Description: Undo unit for TextContainer.SetValue, etc. calls. 
//
// History: 
//  03/03/2004 : [....] - Created
//
//---------------------------------------------------------------------------
 
using System;
using MS.Internal; 
 
namespace System.Windows.Documents
{ 
    // Undo unit for TextContainer.SetValue, etc. calls.
    internal class TextTreePropertyUndoUnit : TextTreeUndoUnit
    {
        //----------------------------------------------------- 
        //
        //  Constructors 
        // 
        //-----------------------------------------------------
 
        #region Constructors

        // Create a new undo unit instance.
        // symbolOffset is where property values will be set. 
        internal TextTreePropertyUndoUnit(TextContainer tree, int symbolOffset, PropertyRecord propertyRecord) : base(tree, symbolOffset)
        { 
            _propertyRecord = propertyRecord; 
        }
 
        #endregion Constructors

        //------------------------------------------------------
        // 
        //  Public Methods
        // 
        //----------------------------------------------------- 

        #region Public Methods 

        // Called by the undo manager.  Restores tree state to its condition
        // when the unit was created.  Assumes the tree state matches conditions
        // just after the unit was created. 
        public override void DoCore()
        { 
            TextPointer position; 

            VerifyTreeContentHashCode(); 

            position = new TextPointer(this.TextContainer, this.SymbolOffset, LogicalDirection.Forward);

            Invariant.Assert(position.GetPointerContext(LogicalDirection.Backward) == TextPointerContext.ElementStart, "TextTree undo unit out of sync with TextTree."); 

            if (_propertyRecord.Value != DependencyProperty.UnsetValue) 
            { 
                this.TextContainer.SetValue(position, _propertyRecord.Property, _propertyRecord.Value);
            } 
            else
            {
                position.Parent.ClearValue(_propertyRecord.Property);
            } 
        }
 
        #endregion Public Methods 

        //------------------------------------------------------ 
        //
        //  Private Fields
        //
        //------------------------------------------------------ 

        #region Private Fields 
 
        // Property/value pair to restore.
        private readonly PropertyRecord _propertyRecord; 

        #endregion Private Fields
    }
} 


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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