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Freezable.WritePreamble Method

Verifies that the Freezable is not frozen and that it is being accessed from a valid threading context. Freezable inheritors should call this method at the beginning of any API that writes to data members that are not dependency properties.

Namespace:  System.Windows
Assembly:  WindowsBase (in WindowsBase.dll)

protected function WritePreamble()
You cannot use methods in XAML.

ExceptionCondition
InvalidOperationException

The Freezable instance is frozen and cannot have its members written to.

This method calls VerifyAccess to verify the threading context is accessible, and it throws an exception if the Freezable instance is already frozen.

Notes to Inheritors:

Classes that derive from Freezable should call WritePreamble before attempting to write to any members that are not dependency properties. If you call WritePreamble in an API, you can omit a call to ReadPreamble.

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

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

.NET Framework

Supported in: 3.5, 3.0

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