.NET Framework Class Library
AspNetCompatibilityRequirementsAttribute Class

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

Inheritance Hierarchy

Namespace:   System.ServiceModel.Activation
Assembly:  System.ServiceModel (in System.ServiceModel.dll)
<[%$TOPIC/ms588069_en-us_VS_110_2_0_0_0_0%]([%$TOPIC/ms588069_en-us_VS_110_2_0_0_0_1%].Class)> _
Public NotInheritable Class AspNetCompatibilityRequirementsAttribute _
	Inherits [%$TOPIC/ms588069_en-us_VS_110_2_0_0_0_2%] _
	Implements [%$TOPIC/ms588069_en-us_VS_110_2_0_0_0_3%]
public sealed class AspNetCompatibilityRequirementsAttribute : [%$TOPIC/ms588069_en-us_VS_110_2_0_1_0_2%], 
public ref class AspNetCompatibilityRequirementsAttribute sealed : public [%$TOPIC/ms588069_en-us_VS_110_2_0_2_0_2%], 
type AspNetCompatibilityRequirementsAttribute =  
        inherit [%$TOPIC/ms588069_en-us_VS_110_2_0_3_0_3%] 
        interface [%$TOPIC/ms588069_en-us_VS_110_2_0_3_0_4%] 

The AspNetCompatibilityRequirementsAttribute type exposes the following members.

Public method AspNetCompatibilityRequirementsAttributeInitializes a new instance of the AspNetCompatibilityRequirementsAttribute class.
Public property RequirementsModeGets or sets the level of ASP.NET compatibility required by the service.
Public property TypeIdWhen implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)
Public method EqualsInfrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
Public method GetHashCodeReturns the hash code for this instance. (Inherited from Attribute.)
Public method GetTypeGets the Type of the current instance. (Inherited from Object.)
Public method IsDefaultAttributeWhen overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public method MatchWhen overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Public method ToStringReturns a string that represents the current object. (Inherited from Object.)
Explicit Interface Implementations
Explicit interface implemetation Private method _AttributeGetIDsOfNamesMaps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetation Private method _AttributeGetTypeInfoRetrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetation Private method _AttributeGetTypeInfoCountRetrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetation Private method _AttributeInvokeProvides access to properties and methods exposed by an object. (Inherited from Attribute.)
Explicit interface implemetation Private method IServiceBehaviorAddBindingParametersAdds custom data that the binding elements can access to support the implementation of the contract.
Explicit interface implemetation Private method IServiceBehaviorApplyDispatchBehaviorChecks that the type of hosting is consistent with the ASP.NET compatibility requirements.
Explicit interface implemetation Private method IServiceBehaviorValidateValidates 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 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.


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

<ServiceContract(Namespace:="http://Microsoft.ServiceModel.Samples")> _
Public Interface ICalculatorSession

    <OperationContract()> _
    Sub Clear()
    <OperationContract()> _
    Sub AddTo(ByVal n As Double)
    <OperationContract()> _
    Sub SubtractFrom(ByVal n As Double)
    <OperationContract()> _
    Sub MultiplyBy(ByVal n As Double)
    <OperationContract()> _
    Sub DivideBy(ByVal n As Double)
    <OperationContract()> _
    Function Equal() As Double 
End Interface
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
        Implements ICalculatorSession

        Property Result() As Double 
            ' Store result in AspNet Session. 
                If (HttpContext.Current.Session("Result") Is Nothing) Then 
                    Return 0D
                End If 
                Return HttpContext.Current.Session("Result")
            End Get 
            Set(ByVal value As Double)
                HttpContext.Current.Session("Result") = value
            End Set 
        End Property 

        Public Sub Clear() _
 Implements ICalculatorSession.Clear
            Result = 0D
        End Sub 

        Public Sub AddTo(ByVal n As Double) _
Implements ICalculatorSession.AddTo
            Result += n
        End Sub 

        Public Sub SubtractFrom(ByVal n As Double) _
Implements ICalculatorSession.SubtractFrom

            Result -= n
        End Sub 

        Public Sub MultiplyBy(ByVal n As Double) _
Implements ICalculatorSession.MultiplyBy

            Result *= n
        End Sub 

        Public Sub DivideBy(ByVal n As Double) _
Implements ICalculatorSession.DivideBy

            Result /= n
        End Sub 

        Public Function Equal() As Double _
Implements ICalculatorSession.Equal

            Return Result
        End Function 
    End Class
[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;
Version Information

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

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.

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