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AspNetCompatibilityRequirementsAttribute Class

Applied to a Windows Communication Foundation (WCF) service to indicate whether that service can be run in ASP.NET compatibility code.

Namespace:  System.ServiceModel.Activation
Assembly:  System.ServiceModel (in System.ServiceModel.dll)

public ref class AspNetCompatibilityRequirementsAttribute sealed : public Attribute, 

When applied to a service implementation class, this attribute indicates whether this service requires or supports ASP.NET compatibility mode to be enabled for the hosting application domain (AppDomain).

AppDomains hosting WCF services can run in two different hosting modes:

  • Mixed Transports Mode (Default): In this mode, WCF services do not participate in the ASP.NET HTTP pipeline. This guarantees that a WCF service behaves consistently, independent of hosting environment and transport.

  • ASP.NET Compatibility Mode: In this mode, WCF services participate in the ASP.NET HTTP pipeline in a manner similar to ASMX services. ASP.NET features such as File Authorization, UrlAuthorization, and HTTP Session State are applicable to WCF services running in this mode.

The hosting mode is controlled by the application-level configuration flag aspNetCompatibilityEnabled.


<serviceHostingEnvironment aspNetCompatibilityEnabled="true"/>


This flag is false by default and thus WCF services run in the Mixed Transports Mode unless you explicitly opt into the ASP.NET compatibility mode.

For more information about ASP.NET compatibility mode, see serviceHostingEnvironment.

Use the RequirementsMode property to do this. At runtime, applications can detect if ASP.NET compatibility mode is enabled by checking the value of the static property AspNetCompatibilityEnabled.

Users must explicitly opt-in for the ASP.NET compatibility mode when implementing the WCF service by setting the RequirementsMode property on the AspNetCompatibilityRequirementsAttribute in the following examples.

No code example is currently available or this language may not be supported.
No code example is currently available or this language may not be supported.


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

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