<supportPortability> Element

Specifies that an application can reference the same assembly in two different implementations of the .NET Framework, by disabling the default behavior that treats the assemblies as equivalent for application portability purposes.

<configuration> Element
  <runtime> Element
    <assemblyBinding> Element for <runtime>
      <etwEnable> Element

<supportPortability PKT="public_key_token" enabled="true|false"/>

Attributes and Elements

The following sections describe attributes, child elements, and parent elements.

Attributes

Attribute	Description
PKT	Required attribute. Specifies the public key token of the affected assembly, as a string.
enabled	Optional attribute. Specifies whether support for portability between implementations of the specified .NET Framework assembly should be enabled.

enabled Attribute

Value	Description
true	Enable support for portability between implementations of the specified .NET Framework assembly. This is the default.
false	Disable support for portability between implementations of the specified .NET Framework assembly. This enables the application to have references to multiple implementations of the specified assembly.

Child Elements

None.

Parent Elements

Element	Description
configuration	The root element in every configuration file used by the common language runtime and .NET Framework applications.
runtime	Contains information about assembly binding and garbage collection.
assemblyBinding	Contains information about assembly version redirection and the locations of assemblies.

Remarks

Beginning with the .NET Framework version 4, support is automatically provided for applications that can use either of two implementations of the .NET Framework, for example either the .NET Framework implementation or the .NET Framework for Silverlight implementation. The two implementations of a particular .NET Framework assembly are seen as equivalent by the assembly binder. In a few scenarios, this application portability feature causes problems. In those scenarios, the <supportPortability> element can be used to disable the feature.

One such scenario is an assembly that has to reference both the .NET Framework implementation and the .NET Framework for Silverlight implementation of a particular reference assembly. For example, a XAML designer written in Windows Presentation Foundation (WPF) might need to reference both the WPF Desktop implementation, for the designer's user interface, and the subset of WPF that is included in the Silverlight implementation. By default, the separate references cause a compiler error, because assembly binding sees the two assemblies as equivalent. This element disables the default behavior, and allows compilation to succeed.

Important
In order for the compiler to pass the information to the common language runtime's assembly-binding logic, you must use the /appconfig compiler option to specify the location of the app.config file that contains this element.

Example

The following example enables an application to have references to both the .NET Framework implementation and the .NET Framework for Silverlight implementation of any .NET Framework assembly that exists in both implementations. The /appconfig compiler option must be used to specify the location of this app.config file.

<configuration>
   <runtime>
      <assemblyBinding>
         <supportPortability PKT="7cec85d7bea7798e" enable="false"/>
         <supportPortability PKT="31bf3856ad364e35" enable="false"/>
      </assemblyBinding>
   </runtime>
</configuration>

See Also

Reference

/appconfig (C# Compiler Options)

Concepts

.NET Framework Assembly Unification Overview