Xamarin表单的Rest + WCF集成

我正在做一个需要连接到WCF服务的Xamarin Forms项目。我必须使用Rest来访问它，所以我选择使用与pcl兼容的RestSharp版本。我已经做过很多基于SOAP的web服务，但这是我第一次尝试Rest，我觉得我错过了一些非常基本的东西。我已经确认，当我进行SOAP调用时，我的web服务功能正确，所以我相信我的设置不正确。

下面是我的web服务的示例代码:

Imports System.IO
Imports System.Net
Imports System.ServiceModel
Imports System.ServiceModel.Description
Imports System.ServiceModel.Web
<ServiceContract()>
Public Interface Iapi
    <WebInvoke(Method:="PUT",
           UriTemplate:="Login/Email/{Email}/Password/{Password}",
           RequestFormat:=WebMessageFormat.Json,
           ResponseFormat:=WebMessageFormat.Json)>
    <OperationContract(AsyncPattern:=True)>
    Function Login(email As String, password As String) As String
End Interface

下面是我尝试调用服务的示例代码:

public void Login(string email, string password)
    {
        RestClient client = new RestClient("http://www.example.com/service.svc/");
        RestRequest request = new RestRequest
        {
            Method = Method.PUT,
            Resource = "Login/Email/{Email}/Password/{Password}",            
            RequestFormat = DataFormat.Json
        };
        request.AddParameter("Email", email, ParameterType.UrlSegment);
        request.AddParameter("Password", password,ParameterType.UrlSegment);
        client.ExecuteAsync(request, response => {
            session = response.Content;
            ActionCompleted(this, new System.EventArgs());
        });            
    }

当我进行上面的调用时，我没有得到异常，只是一个空字符串返回值。在浏览器中也会发生同样的事情。我怀疑我的服务定义。我有几个问题可能有点基础，但我希望将来也能帮助其他WCF/Rest初学者。

1。我的服务定义中的UriTemplate有什么问题?一个合适的UriTemplate是什么样的?

2。对于这种服务调用，我应该使用PUT方法，还是GET或POST更合适?

3。我的web服务定义中还有什么明显缺失的吗?

4。传递完整服务uri (http://www.example.com/service.svc/)到Rest客户端是否正确?

5。对于Rest初学者有任何其他建议，特别是关于WCF-Rest组合吗?

[OperationContract]
[WebGet(UriTemplate  = "Book/{id}")]
Book GetBookById(string id);

<OperationContract()> _ 
<WebGet(UriTemplate:="Book/{id}")> _ 
Function GetBookById(ByVal id As String) As Book

protected static async Task<T> ExecuteRequestAsync<T>(string resource,
    HttpMethod method,
    object body = null,
    IEnumerable<Parameter> parameters = null) where T : new()
{
    var client = new RestClient("http://example.com/rest/service.svc/");
    var req = new RestRequest(resource, method);
    AddRequestKeys(req);
    if (body != null)
        req.AddBody(body);
    if (parameters != null)
    {
        foreach (var p in parameters)
        {
            req.AddParameter(p);
        }
    }
    Func<Task<T>> result = async () =>
    {
        var response = await client.Execute<T>(req);
        if (response.StatusCode == HttpStatusCode.Unauthorized)
            throw new Exception(response.Data.ToString());
        if (response.StatusCode != HttpStatusCode.OK)
            throw new Exception("Error");
        return response.Data;
    };
    return await result();
}

<configuration>
  <system.serviceModel>
    <services>
      <service name="Metadata.Example.SimpleService">
        <endpoint address=""
                  binding="basicHttpBinding"
                  contract="Metadata.Example.ISimpleService" />
      </service>
    </services>
    <behaviors>
    </behaviors>
  </system.serviceModel>
</configuration>