防止跨域请求到我的wcf服务

public class CorsEnabledAttribute : Attribute, IOperationBehavior
{
    public void AddBindingParameters(OperationDescription operationDescription, BindingParameterCollection bindingParameters)
    {
    }

    public void ApplyClientBehavior(OperationDescription operationDescription, ClientOperation clientOperation)
    {
    }

    public void ApplyDispatchBehavior(OperationDescription operationDescription, DispatchOperation dispatchOperation)
    {
        dispatchOperation.Invoker = new CorsEnabledDispatchOperationInvoker(dispatchOperation.Invoker);
    }

    public void Validate(OperationDescription operationDescription)
    {
    }
}

[CorsEnabled]
public string MyServiceMethod(string input)
{
    return "Hello " + input;
}

public class JsonpEncoder : WebContentTypeEncoder
{
    public override string ContentType
    {
        get { return "application/json"; }
    }

    public override bool IsContentTypeSupported(string contentType)
    {
        return contentType.StartsWith("application/json", StringComparison.OrdinalIgnoreCase);
    }

    public override void Write(XmlDictionaryWriter writer, object graph)
    {
        string json = JsonConvert.SerializeObject(graph);
        string callback = HttpContext.Current.Request["callback"];

        if (!string.IsNullOrEmpty(callback))
        {
            HttpContext.Current.Response.Write(callback + "(" + json + ");");
        }
        else
        {
            HttpContext.Current.Response.Write(json);
        }
    }
}

[ServiceContract]
public interface IMyService
{
    [OperationContract]
    [WebGet(ResponseFormat = WebMessageFormat.Json)]
    string MyServiceMethod(string input);
}

public class MyService : IMyService
{
    public string MyServiceMethod(string input)
    {
        WebOperationContext.Current.OutgoingResponse.Format = WebMessageFormat.Json;
        WebOperationContext.Current.OutgoingResponse.ContentType = "application/x-javascript";
        return "Hello " + input;
    }
}