测试方法引发异常：System.Net.WebException：远程服务器返回错误：（400）错误请求

Question

我正在尝试使用C＃中的Webclient将Json中的多个参数解析为RESTful服务。我保留了400错误请求的错误。它在我传递一个参数但在我尝试传递多个时不起作用时有效，请指教：下面的代码在我的Test Methjod中查询RESTful端点

        AuthToken = GetAuthToken();
        var wcProxy = new WebClient();
        wcProxy.Headers[HttpRequestHeader.Authorization] = "Basic " + AuthToken;
        wcProxy.Headers[HttpRequestHeader.Accept] = "application/json";
        wcProxy.Headers[HttpRequestHeader.ContentType] = "application/json";

        var vm = new ValidateBankAccountCriteria
            {
                AccountNumber = "62294444915",
                BankAccountType = BankAccountType.CurrentAccount,
                BranchCode = "254605"
            };

        string payload = JsonConvert.SerializeObject(vm);
        var payloaded = System.Text.ASCIIEncoding.ASCII.GetBytes(payload);

        Byte[] returnData = wcProxy.UploadData(new Uri(wsUrl + "ValidateBankAccount/"), "POST", payloaded);

        var results = Encoding.ASCII.GetString(returnData);
        Assert.IsTrue(results.Contains("NEDBANK"), "call failed");