使用 Data POST POST 方法调用 Web 服务（以 JSON 格式发布数据）

/// <summary>
    /// Post Method with Input/ data to post in JSON format 
    /// </summary>
    /// <returns> Json formated data </returns>
    public string GetJsonData3()
    {
        IOperations _Obj = ClsOperations.GetOperations();
        string url = "http://1.2.3.4:1234/Services/rest/CallService/WebRequest/";
        string inputjson = "{\"@FirstParameter\": \"Value1\",\"@SecondParameter\": \"Value2\",\"@ThirdParameter\": \"Value3\"}";
        string jsonResult = _Obj.GetJsonResult(url, null,inputjson );
        return jsonResult;
    }