$.ajax({
                    type: 'post',
                    url: 'ajax/test.ashx?canshu1=abc',//传递的参数（可有可无）
                    success: function (jsonStr) {
                        //遍历返回的JSON串
                        var Arr = eval('(' + jsonStr + ')');

}

});

---------------------------------------------

这是一般处理程序中的代码

    public void ProcessRequest (HttpContext context) {
        try
        {
            string startdate = context.Request["startdate"];//这是我传递的参数

            DataTable dt = btest.GetHospitalityStatistics(startdate);//获取数据保存到dataTable中
            string jsonStr = DataTableToJson( dt);//将dataTable转换成Json字符串
         
            if (!string.IsNullOrEmpty(jsonStr))
            {
                 context.Response.Write(jsonStr);//返回数据给前端
            }
            else
            {
                context.Response.Write("");
            }
        }
        catch (Exception ex)
        {
            context.Response.Write("-1");
        }
    }
 
    public bool IsReusable {
        get {
            return false;
        }
    }

//将dataTable转换成json 根据自己需要的内容更改
    public static string DataTableToJson( DataTable dt)
    {
       StringBuilder JsonStr = new StringBuilder();

        string columname = "";
        if (dt != null && dt.Rows.Count > 0)
        {
            JsonStr.Append("[");
            for (int i = 0; i < dt.Rows.Count; i++)//行的循环
            {
                //JsonStr.Append("\"");
                //JsonStr.Append(dt.Rows[i]["roomtypename"].ToString());
                JsonStr.Append("{");
                for (int j = 0; j < dt.Columns.Count; j++)//这是列的循环== "System.Decima" ? dt.Rows[i][j].ToString() : "'" + dt.Rows[i][j] + "'" )
                {
                    string tmp = "'" + dt.Columns[j].ColumnName + "':" + dt.Rows[i][j] + "";
                    JsonStr.Append(tmp);
                    if (j < dt.Columns.Count - 1)
                    {
                        JsonStr.Append(",");
                    }
                }
                JsonStr.Append("}");
                if (i < dt.Rows.Count - 1)
                {
                    JsonStr.Append(",");
                }
            }
            JsonStr.Append("]");
        }
        return JsonStr.ToString();
    }

伪代码：

using system.net.http;

using system.net.http.formatting;

HttpClient client = new HttpClient();

var response=await client.PostJsonAsAsync(url,jsonObj);

var responseJson=response.content.ReadAsync<Type>();

你好，帅哥，请问你在手机端，用H5访问麦克风和摄像头可以吗？ 

C#请求获取json？WebClient？？？