DocumentSequenceHighlightLayer.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Framework / System / Windows / Documents / DocumentSequenceHighlightLayer.cs / 1305600 / DocumentSequenceHighlightLayer.cs
                        
                        
                            //---------------------------------------------------------------------------- 
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved.
//  
//
// Description: DocumentSequence's HighlightLayer for TextSelection. 
// 
// History:
//  07/027/2004 : ZhenbinX - Created 
//
//---------------------------------------------------------------------------
namespace System.Windows.Documents
{ 
    using MS.Internal.Documents;
    using System; 
    using System.Diagnostics; 
    using System.Collections;
    using System.Collections.Generic; 

    // A special HighlightLayer that exists only to notify a FixedDocument
    // of changes to its highlights when the highlights are stored on a
    // DocumentSequenceTextContainer. 
    // This layer is set on a FixedDocumentTextContainer that's part of a
    // DocumentSequence.  When the DocumentSequence's highlight layer changes 
    // it determines which sub-documents need to be notified and uses the 
    // instance of this class for each of those documents to notify it.
    // The FixedDoc then uses the DocumentSequence's Highlights directly to 
    // get the highlight information.
    // Note: Some of the methods below are used in constructing the event args
    // but others are not. This class is not intended to be used directly as an
    // actual highlight layer. 
    internal class DocumentSequenceHighlightLayer : HighlightLayer
    { 
        //----------------------------------------------------- 
        //
        //  Constructors 
        //
        //-----------------------------------------------------

        #region Constructors 
        internal DocumentSequenceHighlightLayer(DocumentSequenceTextContainer docSeqContainer)
        { 
            _docSeqContainer = docSeqContainer; 
        }
        #endregion Constructors 

        //------------------------------------------------------
        //
        //  Internal Methods 
        //
        //----------------------------------------------------- 
 
        #region Internal Methods
 
        // Method is not implemented.  Should not need to be called for constructing the event args.
        internal override object GetHighlightValue(StaticTextPointer staticTextPointer, LogicalDirection direction)
        {
            Debug.Assert(false, "This method is not implemented and not expected to be called."); 
            return null;
        } 
 
        // Returns whether or not this text pointer has a highlight on it.  Determines this by checking
        // the highlights of the DocumentSequence. 
        internal override bool IsContentHighlighted(StaticTextPointer staticTextPointer, LogicalDirection direction)
        {
            return this._docSeqContainer.Highlights.IsContentHighlighted(staticTextPointer, direction);
        } 

        // Returns the next change position starting from the passed in StaticTextPointer.  Determines this by checking 
        // the highlights of the DocumentSequence. 
        internal override StaticTextPointer GetNextChangePosition(StaticTextPointer staticTextPointer, LogicalDirection direction)
        { 
            return this._docSeqContainer.Highlights.GetNextHighlightChangePosition(staticTextPointer, direction);
        }

        // Called by the DocumentSequenceTextContainer to communicate changes to its highlight layer 
        // to the FixedDocumentTextContainer which contains this layer.
        internal void RaiseHighlightChangedEvent(IList ranges) 
        { 
            DocumentsTrace.FixedDocumentSequence.Highlights.Trace(string.Format("DSHL.RaiseHighlightChangedEvent ranges={0}", ranges.Count));
            Debug.Assert(ranges.Count > 0); 
            if (this.Changed != null)
            {
                DocumentSequenceHighlightChangedEventArgs args;
                args = new DocumentSequenceHighlightChangedEventArgs(ranges); 
                this.Changed(this, args);
            } 
        } 

        #endregion Internal Methods 

        //------------------------------------------------------
        //
        //  Internal Properties 
        //
        //------------------------------------------------------ 
 
        #region Internal Properties
 
        /// 
        /// Type identifying this layer for Highlights.GetHighlightValue calls.
        /// 
        internal override Type OwnerType 
        {
            get 
            { 
                return typeof(TextSelection);
            } 
        }

        #endregion Internal Properties
 
        //-----------------------------------------------------
        // 
        //  Internal Events 
        //
        //------------------------------------------------------ 

        #region Internal Events

        // Event raised when a highlight range is inserted, removed, moved, or 
        // has a local property value change.
        internal override event HighlightChangedEventHandler Changed; 
 
        #endregion Internal Events
 
        //-----------------------------------------------------
        //
        //  Private Fields
        // 
        //-----------------------------------------------------
 
        #region Private Fields 
        private readonly DocumentSequenceTextContainer _docSeqContainer;
        #endregion Private Fields 


        //-----------------------------------------------------
        // 
        //  Private Classes
        // 
        //------------------------------------------------------ 

        #region Private Classes 
        // Argument for the Changed event, encapsulates a highlight change.
        private class DocumentSequenceHighlightChangedEventArgs : HighlightChangedEventArgs
        {
            // Constructor. 
            internal DocumentSequenceHighlightChangedEventArgs(IList ranges)
            { 
                _ranges = ranges; 
            }
 
            // Collection of changed content ranges.
            internal override IList Ranges
            {
                get 
                {
                    return _ranges; 
                } 
            }
 
            // Type identifying the owner of the changed layer.
            internal override Type OwnerType
            {
                get 
                {
                    return typeof(TextSelection); 
                } 
            }
 
            // Collection of changed content ranges.
            private readonly IList _ranges;
        }
        #endregion Private Classes 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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DocumentSequenceHighlightLayer.cs source code in C# .NET

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