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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)

public abstract class TextSource

The TextSource type exposes the following members.

Protected methodTextSourceInitializes a new instance of the TextSource class.

Public methodEquals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodGetPrecedingTextRetrieves the text span immediately before the specified TextSource position.
Public methodGetTextEffectCharacterIndexFromTextSourceCharacterIndexRetrieves a value that maps a TextSource character index to a TextEffect character index.
Public methodGetTextRunRetrieves a TextRun starting at a specified TextSource position.
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)

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 .

.NET Framework

Supported in: 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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