ChangeBlockUndoRecord.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 / ChangeBlockUndoRecord.cs / 1 / ChangeBlockUndoRecord.cs
                        

                        
                            //---------------------------------------------------------------------------- 
//
// File: ChangeBlockUndoRecord.cs
//
// Description: Undo wrapper for any edit on or through a TextRange or 
//              TextContainer.
// 
//--------------------------------------------------------------------------- 

using System; 
using System.Windows;
using MS.Internal;
using MS.Internal.Documents;
 
namespace System.Windows.Documents
{ 
    // Undo wrapper for any edit on or through a TextRange or TextContainer. 
    internal class ChangeBlockUndoRecord
    { 
        //-----------------------------------------------------
        //
        //  Constructors
        // 
        //-----------------------------------------------------
 
        #region Constructors 

        // Constructor, called when a change block is opening. 
        internal ChangeBlockUndoRecord(ITextContainer textContainer, string actionDescription)
        {
            if (textContainer.UndoManager != null)
            { 
                _undoManager = textContainer.UndoManager;
 
                if (_undoManager.IsEnabled) 
                {
                    // Don't bother opening an undo unit if the owning control is 
                    // still being initialized (ie, programmatic load by parser).
                    if (textContainer.TextView != null)
                    {
                        // Don't bother opening a new undo unit if we're already nested 
                        // inside another.
                        if (_undoManager.OpenedUnit == null) 
                        { 
                            if (textContainer.TextSelection != null)
                            { 
                                _parentUndoUnit = new TextParentUndoUnit(textContainer.TextSelection);
                            }
                            else
                            { 
                                _parentUndoUnit = new ParentUndoUnit(actionDescription);
                            } 
 
                            _undoManager.Open(_parentUndoUnit);
                        } 
                    }
                    else
                    {
                        // If the owning control isn't initialized (parser is still running), 
                        // don't add anything to the undo record.  Instead, clear it.
                        _undoManager.Clear(); 
                    } 
                }
            } 
        }

        #endregion Constructors
 
        //------------------------------------------------------
        // 
        //  Internal Methods 
        //
        //----------------------------------------------------- 

        #region Internal Methods

        // Called when a change block is closing. 
        internal void OnEndChange()
        { 
            // Commit our undo unit. 
            if (_parentUndoUnit != null)
            { 
                IParentUndoUnit openedUnit;

                if (_parentUndoUnit.Container is UndoManager)
                { 
                    openedUnit = ((UndoManager)_parentUndoUnit.Container).OpenedUnit;
                } 
                else 
                {
                    openedUnit = ((IParentUndoUnit)_parentUndoUnit.Container).OpenedUnit; 
                }

                // UIElementPropertyUndoUnit can clear the undo stack if a change is made to a databound property
                if (openedUnit == _parentUndoUnit) 
                {
                    if (_parentUndoUnit is TextParentUndoUnit) 
                    { 
                        ((TextParentUndoUnit)_parentUndoUnit).RecordRedoSelectionState();
                    } 
                    Invariant.Assert(_undoManager != null);
                    _undoManager.Close(_parentUndoUnit, (_parentUndoUnit.LastUnit != null) ? UndoCloseAction.Commit : UndoCloseAction.Discard);
                }
            } 
        }
 
        #endregion Internal Methods 

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

        #region Private Fields 
 
        private readonly UndoManager _undoManager;
 
        private readonly IParentUndoUnit _parentUndoUnit;

        #endregion Private Fields
    } 
}

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

Link Menu

Network programming in C#, Network Programming in VB.NET, Network Programming in .NET
This book is available now!
Buy at Amazon US or
Buy at Amazon UK