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TextSource Class

Provides an abstract class for specifying character data and formatting properties to be used by the TextFormatter object.

Namespace: System.Windows.Media.TextFormatting
Assembly: PresentationCore (in presentationcore.dll)
XML Namespace:

public abstract class TextSource
public abstract class TextSource
public abstract class TextSource
This class is abstract; see Inheritance Hierarchy for derived non-abstract classes usable in XAML.

All access to the text in the TextSource object is through the GetTextRun, which is designed to allow the text layout client to virtualize text in any way it chooses.

TextFormatter is the WPF text engine that provides services for formatting text and breaking text lines. TextFormatter can handle different text character formats and paragraph styles, and includes support for international text layout. Unlike a traditional text API, the TextFormatter interacts with a text layout client through a set of callback methods. It requires the client to provide these methods in an implementation of the TextSource class. The following list describes the three members you must override:


For a complete code sample that shows how to implement a derived TextSource class, see Advanced Text Formatting Sample.


Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0