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ExportProvider.GetExportedValueOrDefault<T> Method (String)

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Gets the exported object with the specified contract name or the default value for the specified type, or throws an exception if there is more than one matching exported object.

Namespace:  System.ComponentModel.Composition.Hosting
Assembly:  System.ComponentModel.Composition (in System.ComponentModel.Composition.dll)

Syntax

'Declaration
Public Function GetExportedValueOrDefault(Of T) ( _
    contractName As String _
) As T

public T GetExportedValueOrDefault<T>(
    string contractName
)

Type Parameters

  • T
    The type of the exported object to return.

Parameters

  • contractName
    Type: System.String
    The contract name of the exported object to return, or nulla null reference (Nothing in Visual Basic) or an empty string ("") to use the default contract name.

Return Value

Type: T
The exported object with the specified contract name, if found; otherwise, the default value for T.

Exceptions

Exception Condition
ImportCardinalityMismatchException

There is more than one exported object with the specified contract name in the CompositionContainer.
ObjectDisposedException

The CompositionContainer object has been disposed of.
CompositionContractMismatchException

The underlying exported object cannot be cast to T.
CompositionException

An error occurred during composition. Errors will contain a collection of errors that occurred.

Remarks

If the exported object is not found, this method returns the appropriate default value for T; for example, zero for integer types, false for Boolean types, and nulla null reference (Nothing in Visual Basic) for reference types.

The contract name is the result of calling the GetContractName method on T.

The contract name is compared by using the Ordinal property to perform a case-sensitive, non-linguistic comparison.

Version Information

Silverlight

Supported in: 5, 4

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.