ASP.NET 内核 Ajax 返回 null

Question

function addTeam() {
    var teamName = $("teamField").val();
    $.ajax({
        type: "POST",
        url: 'AddTeam',
        contentType: "application/json;",
        data:
            { team: "HELLO PLEASE WORK" },
        success: function () {
            alert("URA");
        },
        error: function (error) {
            alert(error);
        }
    });
};

[HttpPost]
        public JsonResult AddTeam(string team)
        {
            teamRepository.Add(new Team { IsDelete = false, Name = team });
            teamRepository.SaveChanges(); 
            return Json(team);
        }

string team awlays returns null. i dont know whats the problem. Searched for same issue in stackoverflow, but no one works for me

Answer 1

It looks like you are sending in an object with the property "team", instead of just a raw string.

You can create a request object as your parameter:

public class AddTeamRequest
{
    public string Team {get; set;}
}

And then use that as your parameter object:

public JsonResult AddTeam(AddTeamRequest request)

Answer 2

You cant get value because you cant get it from html.You should get team name like this. Just add #.

 function addTeam() {
    var teamName = $("#teamField").val();///this line
    $.ajax({
        type: "POST",
        url: 'AddTeam',
        contentType: "application/json;",
        data:
            { team: "HELLO PLEASE WORK" },
        success: function () {
            alert("URA");
        },
        error: function (error) {
            alert(error);
        }
    });
};

Answer 3

You use application/json ,so you put the data into body,if you want to get the data in post method,you can use [FromBody] .And the data you pass need to use JSON.stringify(xxx) to change the data type before ajax . Here is a demo worked:

View:

var team1 = "HELLO PLEASE WORK";
        var team = JSON.stringify(team1) ;
        $.ajax({
            type: "POST",
            url: 'AddTeam',
            contentType: "application/json;charset=utf-8",
            data: team,
            success: function () {
                alert("URA");
            },
            error: function (error) {
                alert(error);
            }
        });

Controller:

[HttpPost]
        public JsonResult AddTeam([FromBody]string team)
        {
            
            return Json(team);
        }

result:

Or you can use contentType: "application/x-www-form-urlencoded", ,so that you don't need to use [FromBody] and don't need to change the data type.