我最近一直在努力执行你所描述的相同的功能。我设法得到它具有以下code工作：

I have recently been trying to implement the same functionality you have described. I have managed to get it working with the following code:

    private readonly AuthenticationServiceClient service = new AuthenticationServiceClient();

    public void SignIn(string userName, string password, bool createPersistentCookie)
    {
        using (new OperationContextScope(service.InnerChannel))
        {
            // login
            service.Login(userName, password, String.Empty, createPersistentCookie);

            // Get the response header
            var responseMessageProperty = (HttpResponseMessageProperty)
                OperationContext.Current.IncomingMessageProperties[HttpResponseMessageProperty.Name];

            string encryptedCookie = responseMessageProperty.Headers.Get("Set-Cookie");

            // parse header to cookie object
            var cookieJar = new CookieContainer();
            cookieJar.SetCookies(new Uri("http://localhost:1062/"), encryptedCookie);
            Cookie cookie = cookieJar.GetCookies(new Uri("http://localhost:1062/"))[0];

            FormsAuthenticationTicket ticket = FormsAuthentication.Decrypt(cookie.Value);
            if (null != ticket)
            {
                //string[] roles = RoleManager.GetRolesFromString(ticket.UserData); 
                HttpContext.Current.User = new GenericPrincipal(new FormsIdentity(ticket), null);
                FormsAuthentication.SetAuthCookie(HttpContext.Current.User.Identity.Name, createPersistentCookie);
            }
        }
    }

这不正是你所描述的评论你的问题。

It does exactly what you have described the comment to your question.

修改

我在这里张贴这code的服务器端部分，以供参考。

I am posting here the Server-Side portion of this code for reference.

public class HttpResponseMessageInspector : BehaviorExtensionElement, IDispatchMessageInspector, IServiceBehavior
{
    public object AfterReceiveRequest(ref Message request, IClientChannel channel, InstanceContext instanceContext)
    {

        HttpRequestMessageProperty httpRequest = request.Properties[HttpRequestMessageProperty.Name]
        as HttpRequestMessageProperty;

        if (httpRequest != null)
        {
            string cookie = httpRequest.Headers[HttpRequestHeader.Cookie];

            if (!string.IsNullOrEmpty(cookie))
            {
                FormsAuthentication.Decrypt(cookie);
                FormsAuthenticationTicket authTicket = FormsAuthentication.Decrypt(cookie);
                string[] roles = PrincipalHelper.GetUserRoles(authTicket);
                var principal = new BreakpointPrincipal(new BreakpointIdentity(authTicket), roles);

                HttpContext.Current.User = principal;                  
            }
            // can deny request here
        }

        return null;
    }
}