XamlType.IsUnknown Property

Gets a value that indicates whether this XamlType represents a type that cannot be resolved in the underlying type system.

Namespace:  System.Xaml
Assembly:  System.Xaml (in System.Xaml.dll)

public bool IsUnknown { get; }

Property Value

Type: System.Boolean
true if this XamlType represents an unresolvable type; otherwise, false.

If you do not use the default internal CLR reflection technique for a XamlType, calls to this property can invoke LookupIsUnknown overrides on XamlType derived classes.

For a load path that involves XamlObjectWriter, a XamlType that has true for IsUnknown cannot be written into an object graph. Under the default implementations in System.Xaml , the XamlObjectWriter.WriteStartObject call throws a XamlObjectWriterException when the relevant XamlType reports true for IsUnknown. You should not pass a XamlType that has IsUnknown as true unless you are prepared to handle the exceptions from XamlObjectWriter, or you have other ways to adjust the XamlObjectWriter behavior or the XAML node stream prior to writing the object graph.

.NET Framework

Supported in: 4.5, 4

.NET Framework Client Profile

Supported in: 4

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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