AspNetCompatibilityRequirementsAttribute Class


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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 sealed class AspNetCompatibilityRequirementsAttribute : Attribute, 


Initializes a new instance of the AspNetCompatibilityRequirementsAttribute class.


Gets or sets the level of ASP.NET compatibility required by the service.


When implemented in a derived class, gets a unique identifier for this Attribute.(Inherited from Attribute.)


This API supports the product infrastructure and is not intended to be used directly from your code. Returns a value that indicates whether this instance is equal to a specified object.(Inherited from Attribute.)


Returns the hash code for this instance.(Inherited from Attribute.)


Gets the Type of the current instance.(Inherited from Object.)


When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class.(Inherited from Attribute.)


When overridden in a derived class, returns a value that indicates whether this instance equals a specified object.(Inherited from Attribute.)


Returns a string that represents the current object.(Inherited from Object.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr)

Maps a set of names to a corresponding set of dispatch identifiers.(Inherited from Attribute.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.GetTypeInfo(UInt32, UInt32, IntPtr)

Retrieves the type information for an object, which can be used to get the type information for an interface.(Inherited from Attribute.)


Retrieves the number of type information interfaces that an object provides (either 0 or 1).(Inherited from Attribute.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr)

Provides access to properties and methods exposed by an object.(Inherited from Attribute.)

System_CAPS_pubinterfaceSystem_CAPS_privmethodIServiceBehavior.AddBindingParameters(ServiceDescription, ServiceHostBase, Collection<ServiceEndpoint>, BindingParameterCollection)

Adds custom data that the binding elements can access to support the implementation of the contract.

System_CAPS_pubinterfaceSystem_CAPS_privmethodIServiceBehavior.ApplyDispatchBehavior(ServiceDescription, ServiceHostBase)

Checks that the type of hosting is consistent with the ASP.NET compatibility requirements.

System_CAPS_pubinterfaceSystem_CAPS_privmethodIServiceBehavior.Validate(ServiceDescription, ServiceHostBase)

Validates the service behavior.

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 aboutASP.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.

Service developers can ensure that their service is only run in ASP.NET Compatibility Mode by setting the RequirementsMode property on the AspNetCompatibilityRequirementsAttribute to Required as shown in the following example

public interface ICalculatorSession
    void Clear();
    void AddTo(double n);
    void SubtractFrom(double n);
    void MultiplyBy(double n);
    void DivideBy(double n);
    double Equals();
[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Required)]
public class CalculatorService : ICalculatorSession
    double result
    {   // Store result in AspNet session.
            if (HttpContext.Current.Session["Result"] != null)
                return (double)HttpContext.Current.Session["Result"];
            return 0.0D;
            HttpContext.Current.Session["Result"] = value;

    public void Clear()


    public void AddTo(double n)
        result += n;

    public void SubtractFrom(double n)
        result -= n;

    public void MultiplyBy(double n)
        result *= n;

    public void DivideBy(double n)
        result /= n;

    public double Equals()
        return result;

.NET Framework
Available since 3.0

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

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