ajax: front-end and back-end json pass value writing

There are many types of contentType in ajax, the default is contentType=application/x-www-form-urlencoded;charset=utf-8;, if you set contentType=application/json;charset=utf-8; it will happen in the background In the case where the parameters cannot be obtained through context.Request.Form[], I will sort out the two methods of post and get below.

post by value

Front-end code, data is a json string:

function PostSendParams() {
    $.ajax({
        type: "post",
        url: "Handler1.ashx",
        contentType: "application/json;charset=utf-8;",
        data: "{ \"contentType\": \"application/json\", \"param2\": \"18\" }",
        dataType: "json",
        success:function(data) {
            alert("data=" + data);
        },
        error:function(error) {
            alert("error=" + error);
        }
    });
}

Background value:

public void ProcessRequest(HttpContext context)
{
    try
    {
        #region Form取值(不行)
        //string contentType = context.Request.Form["contentType"].ToString();
        //string param2 = context.Request.Form["param2"].ToString();
        #endregion

        #region InputStream取值（可以）
        Stream stream = context.Request.InputStream;
        byte[] bytes = new byte[stream.Length];
        stream.Read(bytes, 0, bytes.Length);
        string parameters = Encoding.Default.GetString(bytes);
        JObject jObject = (JObject)JsonConvert.DeserializeObject(parameters);
        string contentType = jObject["contentType"].ToString();
        string param2 = jObject["param2"].ToString(); 
        #endregion                
    }
    catch (Exception ex)
    {
        context.Response.Write("error");
    }
}

Front-end code, data is a json object:

function PostSendParams() {
    $.ajax({
        type: "post",
        url: "Handler1.ashx",
        contentType: "application/json;charset=utf-8;",
        data: { contentType: "application/json", param2: 18 },
        dataType: "json",
        success:function(data) {
            alert("data=" + data);
        },
        error:function(error) {
            alert("error=" + error);
        }
    });
}

Background value:

public void ProcessRequest(HttpContext context)
{
    try
    {
        #region Form取值(不行)
        //string contentType = context.Request.Form["contentType"].ToString();
        //string param2 = context.Request.Form["param2"].ToString();
        #endregion

        #region InputStream取值（不行）
        Stream stream = context.Request.InputStream;
        byte[] bytes = new byte[stream.Length];
        stream.Read(bytes, 0, bytes.Length);
        string parameters = Encoding.Default.GetString(bytes);
        JObject jObject = (JObject)JsonConvert.DeserializeObject(parameters);
        string contentType = jObject["contentType"].ToString();
        string param2 = jObject["param2"].ToString(); 
        #endregion                
    }
    catch (Exception ex)
    {
        context.Response.Write("error");
    }
}

get by value

Front-end code, data is a json string:

function GetSendParams() {
    $.ajax({
        type: "get",
        url: "Handler1.ashx",
        contentType: "application/json;charset=utf-8;",
        data: "{ \"contentType\": \"application/json\", \"param2\": \"18\" }",        
        dataType: "json",
        success: function (data) {
            alert("data=" + data);
        },
        error: function (error) {
            alert("error=" + error);
        }
    });
}

Background value:

public void ProcessRequest(HttpContext context)
{
    try
    {
        #region QueryString取值（不行）
        //string contentType = context.Request.QueryString["contentType"].ToString();
        //string param2 = context.Request.QueryString["param2"].ToString();
        #endregion

        #region InputStream取值（不行）
        Stream stream = context.Request.InputStream;
        byte[] bytes = new byte[stream.Length];
        stream.Read(bytes, 0, bytes.Length);
        string parameters = Encoding.Default.GetString(bytes);
        JObject jObject = (JObject)JsonConvert.DeserializeObject(parameters);
        string contentType = jObject["contentType"].ToString();
        string param2 = jObject["param2"].ToString();
        #endregion
    }
    catch (Exception ex)
    {
        context.Response.Write("error");
    }
}

Front-end code, data is a json object:

function GetSendParams() {
    $.ajax({
        type: "get",
        url: "Handler1.ashx",
        contentType: "application/json;charset=utf-8;",
        data: { contentType: "application/json", param2: 18 },
        dataType: "json",
        success: function (data) {
            alert("data=" + data);
        },
        error: function (error) {
            alert("error=" + error);
        }
    });
}

Background value:

public void ProcessRequest(HttpContext context)
{
    try
    {
        #region QueryString取值（可以）
        string contentType = context.Request.QueryString["contentType"].ToString();
        string param2 = context.Request.QueryString["param2"].ToString();
        #endregion

        #region InputStream取值（不行）
        //Stream stream = context.Request.InputStream;
        //byte[] bytes = new byte[stream.Length];
        //stream.Read(bytes, 0, bytes.Length);
        //string parameters = Encoding.Default.GetString(bytes);
        //JObject jObject = (JObject)JsonConvert.DeserializeObject(parameters);
        //string contentType = jObject["contentType"].ToString();
        //string param2 = jObject["param2"].ToString();
        #endregion
    }
    catch (Exception ex)
    {
        context.Response.Write("error");
    }
}

Summarize

When contentType=application/json;charset=utf-8;, the post value can only be obtained by parsing the data with InputStream in the background of a json string;
when contentType=application/json;charset=utf-8;, The get value can only be obtained by parsing the data with QueryString in the background of the json object.