Span.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Framework / System / Windows / Documents / Span.cs / 1 / Span.cs
                        
                        
                            //---------------------------------------------------------------------------- 
//
// Copyright (C) Microsoft Corporation.  All rights reserved.
//
// Description: Span class - inline element grouping several other inline elements 
//
//--------------------------------------------------------------------------- 
 
using MS.Internal;                  // Invariant.Assert
using System.Windows.Controls;      // TextBlock 
using System.Windows.Markup; // ContentProperty
using System.ComponentModel;        // DesignerSerializationVisibility

namespace System.Windows.Documents 
{
    ///  
    /// Span element used for grouping other Inline elements. 
    /// 
    [ContentProperty("Inlines")] 
    public class Span : Inline
    {
        //-------------------------------------------------------------------
        // 
        // Constructors
        // 
        //------------------------------------------------------------------- 

        #region Constructors 

        /// 
        /// Initializes a new instance of a Span element.
        ///  
        public Span()
        { 
        } 

        ///  
        /// Initializes a new instance of a Span element.
        /// 
        /// 
        /// An Inline element added to this Span as its first child. 
        /// 
        public Span(Inline childInline) : this(childInline, null) 
        { 
        }
 
        /// 
        /// Creates a new Span instance.
        /// 
        ///  
        /// Optional child Inline for the new Span.  May be null.
        ///  
        ///  
        /// Optional position at which to insert the new Span.  May be null.
        ///  
        public Span(Inline childInline, TextPointer insertionPosition)
        {
            if (insertionPosition != null)
            { 
                insertionPosition.TextContainer.BeginChange();
            } 
            try 
            {
                if (insertionPosition != null) 
                {
                    // This will throw InvalidOperationException if schema validity is violated.
                    insertionPosition.InsertInline(this);
                } 

                if (childInline != null) 
                { 
                    this.Inlines.Add(childInline);
                } 
            }
            finally
            {
                if (insertionPosition != null) 
                {
                    insertionPosition.TextContainer.EndChange(); 
                } 
            }
        } 

        /// 
        /// Creates a new Span instance covering existing content.
        ///  
        /// 
        /// Start position of the new Span. 
        ///  
        /// 
        /// End position of the new Span. 
        /// 
        /// 
        /// start and end must both be parented by the same Paragraph, otherwise
        /// the method will raise an ArgumentException. 
        /// 
        public Span(TextPointer start, TextPointer end) 
        { 
            if (start == null)
            { 
                throw new ArgumentNullException("start");
            }
            if (end == null)
            { 
                throw new ArgumentNullException("start");
            } 
            if (start.TextContainer != end.TextContainer) 
            {
                throw new ArgumentException(SR.Get(SRID.InDifferentTextContainers, "start", "end")); 
            }
            if (start.CompareTo(end) > 0)
            {
                throw new ArgumentException(SR.Get(SRID.BadTextPositionOrder, "start", "end")); 
            }
 
            start.TextContainer.BeginChange(); 
            try
            { 
                start = TextRangeEditTables.EnsureInsertionPosition(start);
                Invariant.Assert(start.Parent is Run);
                end = TextRangeEditTables.EnsureInsertionPosition(end);
                Invariant.Assert(end.Parent is Run); 

                if (start.Paragraph != end.Paragraph) 
                { 
                    throw new ArgumentException(SR.Get(SRID.InDifferentParagraphs, "start", "end"));
                } 

                // If start or end positions have a Hyperlink ancestor, we cannot split them.
                Inline nonMergeableAncestor;
                if ((nonMergeableAncestor = start.GetNonMergeableInlineAncestor()) != null) 
                {
                    throw new InvalidOperationException(SR.Get(SRID.TextSchema_CannotSplitElement, nonMergeableAncestor.GetType().Name)); 
                } 
                if ((nonMergeableAncestor = end.GetNonMergeableInlineAncestor()) != null)
                { 
                    throw new InvalidOperationException(SR.Get(SRID.TextSchema_CannotSplitElement, nonMergeableAncestor.GetType().Name));
                }

                TextElement commonAncestor = TextElement.GetCommonAncestor((TextElement)start.Parent, (TextElement)end.Parent); 

                while (start.Parent != commonAncestor) 
                { 
                    start = SplitElement(start);
                } 
                while (end.Parent != commonAncestor)
                {
                    end = SplitElement(end);
                } 

                if (start.Parent is Run) 
                { 
                    start = SplitElement(start);
                } 
                if (end.Parent is Run)
                {
                    end = SplitElement(end);
                } 

                Invariant.Assert(start.Parent == end.Parent); 
                Invariant.Assert(TextSchema.IsValidChild(/*position*/start, /*childType*/typeof(Span))); 

                this.Reposition(start, end); 
            }
            finally
            {
                start.TextContainer.EndChange(); 
            }
        } 
 
        #endregion Constructors
 
        //--------------------------------------------------------------------
        //
        // Public Properties
        // 
        //-------------------------------------------------------------------
 
        #region Public Properties 

        ///  
        /// Collection of Inline items contained in this Section.
        /// 
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
        public InlineCollection Inlines 
        {
            get 
            { 
                return new InlineCollection(this, /*isOwnerParent*/true);
            } 
        }

        #endregion Public Properties
 
        //--------------------------------------------------------------------
        // 
        // Internal Methods 
        //
        //-------------------------------------------------------------------- 

        #region Internal Methods

        ///  
        /// This method is used by TypeDescriptor to determine if this property should
        /// be serialized. 
        ///  
        [EditorBrowsable(EditorBrowsableState.Never)]
        public bool ShouldSerializeInlines(XamlDesignerSerializationManager manager) 
        {
            return manager != null && manager.XmlWriter == null;
        }
 
        #endregion Internal Methods
 
        //------------------------------------------------------------------- 
        //
        // Private Methods 
        //
        //--------------------------------------------------------------------

        #region Private Methods 

        // Splits the parent TextElement of a TextPointer, returning a TextPointer 
        // between the two split halves. 
        // If the TextPointer is adjacent to one of the TextElement's edges,
        // this method does not split the element, and instead returns a pointer 
        // adjacent to the bordered edge, outside the TextElemetn scope.
        private TextPointer SplitElement(TextPointer position)
        {
            if (position.GetPointerContext(LogicalDirection.Backward) == TextPointerContext.ElementStart) 
            {
                position = position.GetNextContextPosition(LogicalDirection.Backward); 
            } 
            else if (position.GetPointerContext(LogicalDirection.Forward) == TextPointerContext.ElementEnd)
            { 
                position = position.GetNextContextPosition(LogicalDirection.Forward);
            }
            else
            { 
                position = TextRangeEdit.SplitElement(position);
            } 
 
            return position;
        } 

        #endregion Private Methods
    }
} 

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