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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
//
// 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
{
/// <summary>
/// Span element used for grouping other Inline elements.
/// </summary>
[ContentProperty("Inlines")]
public class Span : Inline
{
//-------------------------------------------------------------------
//
// Constructors
//
//-------------------------------------------------------------------
#region Constructors
/// <summary>
/// Initializes a new instance of a Span element.
/// </summary>
public Span()
{
}
/// <summary>
/// Initializes a new instance of a Span element.
/// </summary>
/// <param name="childInline">
/// An Inline element added to this Span as its first child.
/// </param>
public Span(Inline childInline) : this(childInline, null)
{
}
/// <summary>
/// Creates a new Span instance.
/// </summary>
/// <param name="childInline">
/// Optional child Inline for the new Span. May be null.
/// </param>
/// <param name="insertionPosition">
/// Optional position at which to insert the new Span. May be null.
/// </param>
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();
}
}
}
/// <summary>
/// Creates a new Span instance covering existing content.
/// </summary>
/// <param name="start">
/// Start position of the new Span.
/// </param>
/// <param name="end">
/// End position of the new Span.
/// </param>
/// <remarks>
/// start and end must both be parented by the same Paragraph, otherwise
/// the method will raise an ArgumentException.
/// </remarks>
public Span(TextPointer start, TextPointer end)
{
ArgumentNullException.ThrowIfNull(start);
ArgumentNullException.ThrowIfNull(end);
if (start.TextContainer != end.TextContainer)
{
throw new ArgumentException(SR.Format(SR.InDifferentTextContainers, "start", "end"));
}
if (start.CompareTo(end) > 0)
{
throw new ArgumentException(SR.Format(SR.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.Format(SR.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.Format(SR.TextSchema_CannotSplitElement, nonMergeableAncestor.GetType().Name));
}
if ((nonMergeableAncestor = end.GetNonMergeableInlineAncestor()) != null)
{
throw new InvalidOperationException(SR.Format(SR.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
/// <value>
/// Collection of Inline items contained in this Section.
/// </value>
[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
public InlineCollection Inlines
{
get
{
return new InlineCollection(this, /*isOwnerParent*/true);
}
}
#endregion Public Properties
//-------------------------------------------------------------------
//
// Internal Methods
//
//-------------------------------------------------------------------
#region Internal Methods
/// <summary>
/// This method is used by TypeDescriptor to determine if this property should
/// be serialized.
/// </summary>
[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
}
}
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