send multiple parameters to asp.net core 3 mvc action using post method

Question

There is problem in sending ajax requests that have multiple parameters to asp.net mvc core 3 action using http post method. the parameters do not bind. In dot net framework asp.net web api there was similar limitation but not in asp.net mvc actions. I want to know is there work around this in asp.net core 3 mvc or is this the new limitation? action:

public string SomeAction([FromBody]string param1, [FromBody]IEnumerable<SomeType> param2, [FromBody]IEnumerable<SomeType> param3)
{
       //param1 and param2 and param3 are null
}

client:

    $.ajax({
        contentType: 'application/json',
        data: JSON.stringify({
            "param1": "someString",
            "param2": someList,
            "param3": someList
        }),
        type: "POST",
        dataType: "json",
        url: "/SomeController/SomeAction",
        success: function (result) {
        },
        error: function (error) {
            console.error(error);
        }
    }
    );

Can you wrap parameters with an object and try with [FromBody] attribute? — Damith
– Damith, Commented Oct 22, 2019 at 11:14
@Ma core is a complete rewrite of the previous version. There are things that worked in mvc 5+ that have been refined in the new version. — Nkosi
– Nkosi, Commented Oct 22, 2019 at 11:18

Nkosi · Accepted Answer · 2019-10-22 11:15:59Z

2

With the new version actions need to be explicit about what and where they expected to bind models from.

Create a mode to hold all the required data

public class SomeActionModel {
    public string param1 { get; set; }
    public IEnumerable<SomeType> param2 { get; set; }
    public IEnumerable<SomeType> param3 { get; set; }
}

Update the action to expect the data from the body of the request

public IActionResult SomeAction([FromBody] SomeActionModel model) {
    if(ModelState.IsValid) {
        string param1 = model.param1;
        IEnumerable<SomeType> param2 = model.param2;
        IEnumerable<SomeType> param3 = model.param3;

        //...

        return Ok();
    }

    return BadRequest(ModelState);
}

The client should also send the data in the correct format

var model = {
    param1: GeometricNetworkTrace_Class.flags,
    param2: GeometricNetworkTrace_Class.barriers,
    param3: feederIds
};

$.ajax({
    contentType: 'application/json',
    data: JSON.stringify(model),
    type: "POST",
    dataType: "json",
    url: "/controllerName/actionName",
    success: function (result) {
    },
    error: function (error) {
        console.error(error);
    }
});

Reference Model Binding in ASP.NET Core

answered Oct 22, 2019 at 11:15

Nkosi

249k38 gold badges472 silver badges506 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Chris Pratt Over a year ago

Not with JSON. JSON is very literally "object notation", so you need to bind it to an object, not a bunch of different params. You can send via x-www-form-urlencoded, and bind that to multiple params, because it's just key-value pairs.

Ivan G. · Accepted Answer · 2019-10-31 14:57:39Z

1

The reason for a single [FromBody] parameter is described in Parameter Binding in ASP.NET Web API. The request body might be stored in a non-buffered stream that can only be read once.

With a custom model binder you can get around it. See Posting JavaScript types to MVC 6 in .NET core, using Ajax.

edited Oct 31, 2019 at 14:57

Ivan G.

5,2452 gold badges44 silver badges68 bronze badges

answered Oct 31, 2019 at 8:19

Peter

111 bronze badge

Comments

UNOPARATOR · Accepted Answer · 2019-10-22 11:11:44Z

-2

Try adding [FromBody] attribute in your controller signature.

public string SomeAction([FromBody] string param1, IEnumerable<SomeType> param2, IEnumerable<SomeType> param3)
{
       //param1 and param2 and param3 are null
}

answered Oct 22, 2019 at 11:11

UNOPARATOR

7061 gold badge6 silver badges18 bronze badges

2 Comments

Malik Haseeb Over a year ago

FromBody attribute is used where we have complex object. And when we try to tell the mvc that the requested data is with in the body of the request. But here the parameters of the function you are specifying are just the simple types not the complex object

UNOPARATOR Over a year ago

Even if it does not look like a complex object, the 2nd & 3rd params are IEnumerable<SomeType>. SomeType may or may not be a complex type, and Enumerable when used in querystring can see easily lead to [a huge querystring & some problems] (stackoverflow.com/a/48230425/12163640).

Collectives™ on Stack Overflow

send multiple parameters to asp.net core 3 mvc action using post method

3 Answers 3

1 Comment

Comments

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related