TextParentUndoUnit.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Framework / System / Windows / Documents / TextParentUndoUnit.cs / 1305600 / TextParentUndoUnit.cs
                        
                        
                            //---------------------------------------------------------------------------- 
//---------------------------------------------------------------------------
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved. 
// 
// 
// Description: 
//
//      See spec at http://avalon/uis/Stock%20Services/Undo%20spec.htm 
//
// History:
//  03/23/2004 : eveselov - created
// 
//---------------------------------------------------------------------------
using System; 
using MS.Internal; 
using System.Windows.Input;
using System.Windows.Controls; 
using System.Windows.Documents.Internal;
using System.Windows.Threading;
using System.ComponentModel;
using System.Windows.Media; 
using System.Windows.Markup;
using System.Text; 
using MS.Utility; 
using MS.Internal.Documents;
 
namespace System.Windows.Documents
{
    /// 
    /// TextParentUndoUnit 
    /// 
    internal class TextParentUndoUnit : ParentUndoUnit 
    { 
        //-----------------------------------------------------
        // 
        //  Constructors
        //
        //------------------------------------------------------
 
        #region Constructors
 
        ///  
        /// Constructor
        ///  
        /// 
        /// TextSelection before executing the operation.
        /// 
        internal TextParentUndoUnit(ITextSelection selection) 
            : this(selection, selection.AnchorPosition, selection.MovingPosition)
        { 
        } 

        internal TextParentUndoUnit(ITextSelection selection, ITextPointer anchorPosition, ITextPointer movingPosition) 
            : base(String.Empty)
        {
            _selection = selection;
 
            _undoAnchorPositionOffset = anchorPosition.Offset;
            _undoAnchorPositionDirection = anchorPosition.LogicalDirection; 
            _undoMovingPositionOffset = movingPosition.Offset; 
            _undoMovingPositionDirection = movingPosition.LogicalDirection;
 
            // Bug 1706768: we are seeing unitialized values when the undo
            // undo is pulled off the undo stack. _redoAnchorPositionOffset
            // and _redoMovingPositionOffset are supposed to be initialized
            // with calls to RecordRedoSelectionState before that happens. 
            //
            // This code path is being left enabled in DEBUG to help track down 
            // the underlying bug post V1. 
#if DEBUG
            _redoAnchorPositionOffset = -1; 
            _redoMovingPositionOffset = -1;
#else
            _redoAnchorPositionOffset = 0;
            _redoMovingPositionOffset = 0; 
#endif
        } 
 
        /// 
        /// Creates a redo unit from an undo unit. 
        /// 
        protected TextParentUndoUnit(TextParentUndoUnit undoUnit)
            : base(String.Empty)
        { 
            _selection = undoUnit._selection;
 
            _undoAnchorPositionOffset = undoUnit._redoAnchorPositionOffset; 
            _undoAnchorPositionDirection = undoUnit._redoAnchorPositionDirection;
            _undoMovingPositionOffset = undoUnit._redoMovingPositionOffset; 
            _undoMovingPositionDirection = undoUnit._redoMovingPositionDirection;

            // Bug 1706768: we are seeing unitialized values when the undo
            // undo is pulled off the undo stack. _redoAnchorPositionOffset 
            // and _redoMovingPositionOffset are supposed to be initialized
            // with calls to RecordRedoSelectionState before that happens. 
            // 
            // This code path is being left enabled in DEBUG to help track down
            // the underlying bug post V1. 
#if DEBUG
            _redoAnchorPositionOffset = -1;
            _redoMovingPositionOffset = -1;
#else 
            _redoAnchorPositionOffset = 0;
            _redoMovingPositionOffset = 0; 
#endif 
        }
 
        #endregion Constructors

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

        #region Public Methods 

        /// 
        /// Implements IUndoUnit::Do().  For IParentUndoUnit, this means iterating through
        /// all contained units and calling their Do(). 
        /// 
        public override void Do() 
        { 
            base.Do(); // Note: TextParentUndoUnit will be created here by our callback CreateParentUndoUnitForSelf.
 
            ITextContainer textContainer = _selection.Start.TextContainer;
            ITextPointer anchorPosition = textContainer.CreatePointerAtOffset(_undoAnchorPositionOffset, _undoAnchorPositionDirection);
            ITextPointer movingPosition = textContainer.CreatePointerAtOffset(_undoMovingPositionOffset, _undoMovingPositionDirection);
 
            _selection.Select(anchorPosition, movingPosition);
 
            _redoUnit.RecordRedoSelectionState(); 
        }
 
        #endregion Public Methods

        //------------------------------------------------------
        // 
        //  Protected Methods
        // 
        //----------------------------------------------------- 

        #region Protected Methods 

        /// 
        /// Implements a callback called from base.Do method for
        /// creating appropriate ParentUndoUnit for redo. 
        /// 
        ///  
        protected override IParentUndoUnit CreateParentUndoUnitForSelf() 
        {
            _redoUnit = CreateRedoUnit(); 
            return _redoUnit;
        }

        protected virtual TextParentUndoUnit CreateRedoUnit() 
        {
            return new TextParentUndoUnit(this); 
        } 

        protected void MergeRedoSelectionState(TextParentUndoUnit undoUnit) 
        {
            _redoAnchorPositionOffset = undoUnit._redoAnchorPositionOffset;
            _redoAnchorPositionDirection = undoUnit._redoAnchorPositionDirection;
            _redoMovingPositionOffset = undoUnit._redoMovingPositionOffset; 
            _redoMovingPositionDirection = undoUnit._redoMovingPositionDirection;
        } 
 
        #endregion Protected Methods
 
        //------------------------------------------------------
        //
        //  Internal Methods
        // 
        //-----------------------------------------------------
 
        #region Internal Methods 

        ///  
        /// This method should be called just before the undo unit is closed.  It will capture
        /// the current selectionStart and selectionEnd offsets for use later when this undo unit
        /// gets Redone.
        ///  
        internal void RecordRedoSelectionState()
        { 
            RecordRedoSelectionState(_selection.AnchorPosition, _selection.MovingPosition); 
        }
 
        /// 
        /// This method should be called just before the undo unit is closed.  It will capture
        /// the current selectionStart and selectionEnd offsets for use later when this undo unit
        /// gets Redone. 
        /// 
        internal void RecordRedoSelectionState(ITextPointer anchorPosition, ITextPointer movingPosition) 
        { 
            _redoAnchorPositionOffset = anchorPosition.Offset;
            _redoAnchorPositionDirection = anchorPosition.LogicalDirection; 
            _redoMovingPositionOffset = movingPosition.Offset;
            _redoMovingPositionDirection = movingPosition.LogicalDirection;
        }
 
        #endregion Internal Methods
 
        //----------------------------------------------------- 
        //
        //  Private Fields 
        //
        //-----------------------------------------------------

        #region Private Fields 

        private readonly ITextSelection _selection; 
 
        private readonly int _undoAnchorPositionOffset;
        private readonly LogicalDirection _undoAnchorPositionDirection; 

        private readonly int _undoMovingPositionOffset;
        private readonly LogicalDirection _undoMovingPositionDirection;
 
        private int _redoAnchorPositionOffset;
        private LogicalDirection _redoAnchorPositionDirection; 
 
        private int _redoMovingPositionOffset;
        private LogicalDirection _redoMovingPositionDirection; 

        private TextParentUndoUnit _redoUnit;

#if DEBUG 
        // Debug-only unique identifier for this instance.
        private readonly int _debugId = _debugIdCounter++; 
 
        // Debug-only id counter.
        private static int _debugIdCounter; 
#endif
        #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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