TextTreeInsertElementUndoUnit.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 / TextTreeInsertElementUndoUnit.cs / 1 / TextTreeInsertElementUndoUnit.cs
                        

                        
                            //---------------------------------------------------------------------------- 
//
// File: TextTreeInsertElementUndoUnit.cs
//
// Description: Undo unit for TextContainer.InsertElement calls. 
//
// History: 
//  03/03/2004 : [....] - Created 
//
//--------------------------------------------------------------------------- 

using System;
using MS.Internal;
 
namespace System.Windows.Documents
{ 
    // Undo unit for TextContainer.InsertElement calls. 
    internal class TextTreeInsertElementUndoUnit : TextTreeUndoUnit
    { 
        //-----------------------------------------------------
        //
        //  Constructors
        // 
        //-----------------------------------------------------
 
        #region Constructors 

        // Creates a new undo unit instance. 
        // symbolOffset should be just before the start edge of the TextElement to remove.
        // If deep is true, this unit will undo not only the scoping element
        // insert, but also all content scoped by the element.
        internal TextTreeInsertElementUndoUnit(TextContainer tree, int symbolOffset, bool deep) : base(tree, symbolOffset) 
        {
            _deep = deep; 
        } 

        #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 start; 
            TextPointer end; 
            TextElement element;
 
            VerifyTreeContentHashCode();

            start = new TextPointer(this.TextContainer, this.SymbolOffset, LogicalDirection.Forward);
 
            Invariant.Assert(start.GetPointerContext(LogicalDirection.Forward) == TextPointerContext.ElementStart, "TextTree undo unit out of sync with TextTree.");
 
            element = start.GetAdjacentElementFromOuterPosition(LogicalDirection.Forward); 

            if (_deep) 
            {
                // Extract the element and its content.
                end = new TextPointer(this.TextContainer, element.TextElementNode, ElementEdge.AfterEnd);
                this.TextContainer.DeleteContentInternal(start, end); 
            }
            else 
            { 
                // Just extract the element, not its content.
                this.TextContainer.ExtractElementInternal(element); 
            }
        }

        #endregion Public Methods 

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

        #region Private Fields
 
        // If true, this unit tracks a TextElement and its scoped content.
        // Otherwise, this unit only tracks the TextElement. 
        private readonly bool _deep; 

        #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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