The following code example shows how to implement IInstanceProvider that provides "singleton" behavior; it always returns the same service instance and does not recycle it.
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public class ObjectProviderBehavior : IInstanceProvider
{
string message;
SampleService service = null;
public ObjectProviderBehavior(string msg)
{
Console.WriteLine("The non-default constructor has been called.");
this.message = msg;
this.service = new SampleService("Singleton sample service.");
}
#region IInstanceProvider Members
public object GetInstance(InstanceContext instanceContext, System.ServiceModel.Channels.Message message)
{
Console.WriteLine("GetInstance is called:");
return this.service;
}
public object GetInstance(InstanceContext instanceContext)
{
Console.WriteLine("GetInstance is called:");
return this.service;
}
public void ReleaseInstance(InstanceContext instanceContext, object instance)
{
Console.WriteLine("ReleaseInstance is called. The SingletonBehaviorAttribute never releases.");
}
#endregion
}
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The following code example shows how to implement a custom attribute that implements IContractBehavior to insert the custom service instance provider. It also implements IContractBehaviorAttribute, which binds its use to a specific contract.
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public class SingletonBehaviorAttribute : Attribute, IContractBehaviorAttribute, IContractBehavior
{
#region IContractBehaviorAttribute Members
public Type TargetContract
{
get { return typeof(ISampleService); }
}
#endregion
#region IContractBehavior Members
public void AddBindingParameters(ContractDescription description, ServiceEndpoint endpoint, System.ServiceModel.Channels.BindingParameterCollection parameters)
{
return;
}
public void ApplyClientBehavior(ContractDescription description, ServiceEndpoint endpoint, ClientRuntime clientRuntime)
{
return;
}
public void ApplyDispatchBehavior(ContractDescription description, ServiceEndpoint endpoint, DispatchRuntime dispatch)
{
dispatch.InstanceProvider = new ObjectProviderBehavior("Custom ObjectProviderBehavior constructor.");
}
public void Validate(ContractDescription description, ServiceEndpoint endpoint)
{
return;
}
#endregion
}
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