Passing multiple POST parameters in ASP.NET Core controller

Question

I have the following controller method:

[HttpPost]
public IActionResult AddNewMessage(string recipientUserId, string message)
{
    var currentLoggedInUserId = this.User.FindFirstValue(ClaimTypes.NameIdentifier);

    _chatMessageRepository.AddNewMessage(currentLoggedInUserId, recipientUserId, message);

    return Ok();
}

And I am trying to send data to it, using the following JQuery code:

var data = {
    recipientUserId: selectedUser,
    message: message
};

$.ajax({
    url: '/api/chatmessages',
    type: 'POST',
    data: data,
    success: function (data) {
        alert(data.success);
    },
    error: function () {
        alert("error");
    }
});

The result of this code, is that I get the request on my controller, but the parameters are always NULL no matter what. Additionally, I tried to call the function JSON.Stringify() upon the data, before sending them, but it did not do any difference. Keep in mind that I am devilishly trying to avoid to use a model class in this scenario, for project related reasons.

You need to create a model. Apply the FromBody attribute to a parameter to populate its properties from the body of an HTTP request. Don't apply [FromBody] to more than one parameter per action method. Once the request stream is read by an input formatter, it's no longer available to be read again for binding other [FromBody] parameters. — Xordal
– Xordal, Commented Oct 26, 2020 at 17:55

Yinqiu · Accepted Answer · 2020-10-27 14:56:01Z

5

Since you are passing a Json type object, you can only use the object type to accept it in the background.

If you want to receive two string type parameters, there are generally two methods.

The first is as @David Edel said, you can pass values in querystring.

In the second method, you can pass values in data in Ajax, like the following:

$.ajax({
url: '/api/AddNewMessage',
type: 'POST',
data: { recipientUserId: selectedUser, message: message },
success: function (data) {
    alert(data.success);
},
error: function () {
    alert("error");
}

Your Action:

[HttpPost]
public IActionResult AddNewMessage(string recipientUserId, string message)
{
//...
return Ok();
}

edited Oct 27, 2020 at 14:56

answered Oct 27, 2020 at 2:15

Yinqiu

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2 Comments

blacklister Over a year ago

Unfortunately doing this makes me receive a request with the arguments recipientUserId and message being null.

Yinqiu Over a year ago

Because the route in your Ajax does not match your Action, the Ajax request was not sent successfully. You can access this method, which may be the form submission behavior, so please modify the route in your Ajax to match the Action match.

David Edel · Accepted Answer · 2020-10-26 20:02:33Z

2

Your controller method right now accepts the parameters from the url

The correct way to call it would be:

$.ajax({
url: '/api/chatmessages?recipientUserId=selectedUser&message=message',
type: 'POST',
success: function (data) {
    alert(data.success);
},
error: function () {
    alert("error");
}
});

It is common for a post method to accept the payload in the body of the request, you can modify your controller method like this:

[HttpPost]
public IActionResult AddNewMessage(YourCustomClass model)
{
    var currentLoggedInUserId = this.User.FindFirstValue(ClaimTypes.NameIdentifier);

    _chatMessageRepository.AddNewMessage(currentLoggedInUserId, model.recipientUserId, model.message);

    return Ok();
}

There is also a convention to put this attribute [FromBody] in your controller method like this: (It will also work without it)

[HttpPost]
public IActionResult AddNewMessage([FromBody]YourCustomClass model )

answered Oct 26, 2020 at 20:02

David Edel

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1 Comment

blacklister Over a year ago

I don't know if i need to setup anything else, but with this solution I did not manage to make it work, since I do not receive a request to my action method at all. Nevertheless, I managed to make it work by creating a model exactly like you showed (even though it's something that I do not prefer for this project), and keeping my original javascript Ajax call, with the small modification of stringifying my data before sending them. I don't know why it works like that, but it does.

Tomas Tomov · Accepted Answer · 2020-10-26 19:11:35Z

1

Make a class, lets say Message, which has properties recepientUserId and UserId and then replace the two parameters in your controller method with the Message class and add [FromBody] before it. With this u point out that the asp.net should try to map your data from the request's body

answered Oct 26, 2020 at 19:11

Tomas Tomov

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