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InstanceContextMode Enum

  • Reference

Definition

Namespace:
System.ServiceModel
Assembly:
System.ServiceModel.Primitives.dll
Assembly:
System.ServiceModel.dll
Assembly:
System.Private.ServiceModel.dll
Package:
System.ServiceModel.Primitives v8.0.0
Package:
System.Private.ServiceModel v4.10.3
Source:
InstanceContextMode.cs
Source:
InstanceContextMode.cs
Source:
InstanceContextMode.cs

Specifies the number of service instances available for handling calls that are contained in incoming messages.

public enum class InstanceContextMode
public enum InstanceContextMode
type InstanceContextMode = 
Public Enum InstanceContextMode
Inheritance
Object
ValueType
Enum
InstanceContextMode

Fields

PerCall 1

A new InstanceContext object is created prior to and recycled subsequent to each call.
PerSession 0

A new InstanceContext object is created for each session. If the channel does not create a session this value behaves as if it were PerCall.
Single 2

Only one InstanceContext object is used for all incoming calls and is not recycled subsequent to the calls. If a service object does not exist, one is created.

Examples

The following code illustrates how to set the InstanceContextMode for a service class:

// Service class which implements the service contract.
[ServiceBehavior(InstanceContextMode=InstanceContextMode.PerSession)]
public class CalculatorService : ICalculator
{
    public double Add(double n1, double n2)
    {
        return n1 + n2;
    }

    public double Subtract(double n1, double n2)
    {
        return n1 - n2;
    }

    public double Multiply(double n1, double n2)
    {
        return n1 * n2;
    }

    public double Divide(double n1, double n2)
    {
        return n1 / n2;
    }
}

' Service class which implements the service contract.
Public Class CalculatorService
Implements ICalculator

    Public Function Add(n1 As Double, n2 As Double) As Double Implements ICalculator.Add
        Return n1 + n2
    End Function

    Public Function Subtract(n1 As Double, n2 As Double) As Double Implements ICalculator.Subtract
        Return n1 - n2
    End Function

    Public Function Multiply(n1 As Double, n2 As Double) As Double Implements ICalculator.Multiply
        Return n1 * n2
    End Function

    Public Function Divide(n1 As Double, n2 As Double) As Double Implements ICalculator.Divide
        Return n1 / n2
    End Function

End Class

Remarks

The System.ServiceModel.InstanceContext class manages the association between the channel and the user-defined service objects. Use the InstanceContextMode enumeration with the ServiceBehaviorAttribute.InstanceContextMode property to specify the lifetime of the InstanceContext object. Windows Communication Foundation (WCF) can create a new InstanceContext object for every call, every session, or specify that the InstanceContext object is bound to a single service object. For a working example, see Instancing.

The Single value specifies that a single InstanceContext object should be used for the lifetime of the service. Several caveats are associated with the Single value:

Applies to

See also