How to pass multiple json array to controller from ajax?

The issue is with the following line:

data: {hobiler : hobiler,ilgiAlanlar : ilgiAlanlar}

This is an object in javascript. The equivalent in c# should be:

public class MyData {
    public List<HobilerVM> hobiler;
    public List<IlgiAlanlarVM> ilgiAlanlar;
}

And then in your controller:

    [HttpPost]
    public async Task<JsonResult> HobiVeIlgiAlanlariniKaydetGuncelle([FromBody] MyData data)
    {
       //When i put second parameter, both of them comes with null    
    }

For more information, check Why does ASP.NET Web API allow only one parameter for POST method?

Web API doesn’t allow you to pass multiple complex objects in the method signature of a Web API controller method — you can post only a single value to a Web API action method. This value in turn can even be a complex object. It is possible to pass multiple values though on a POST or a PUT operation by mapping one parameter to the actual content and the remaining ones via query strings.Reference: How to pass multiple parameters to Web API controller methods and How WebAPI does Parameter Binding

Solution

public class ComplexObject {
   property List<HobilerVM> Hobiler { get; set; }
   property List<IlgiAlanlarVM> IlgiAlanlar { get; set; }
}

[HttpPost]
public async Task<JsonResult> HobiVeIlgiAlanlariniKaydetGuncelle([FromBody] ComplexObject data)
{
 //When i put second parameter, both of them comes with null    
}

Happy coding, cheers!

I tried your code and it works fine for me except for some things.

First your second parameter has a different ViewModel on what you have posted on your code:

public class IlgiAlanVM
{
   public int id { get; set; }
   public string value { get; set; }
}

But on your parameter, you are using a different ViewModel:

([FromBody] List<HobilerVM> hobiler, List<IlgiAlanlarVM> ilgiAlanlar)

As you can see here, IlgiAlanVM is different on List<IlgiAlanlarVM>

Second, I just I used the same code but without the [FromBody]. So that would be:

//I already edited your List of Model here on the second parameter from IlgiAlanVM to IlgiAlanlarVM
[HttpPost]
public async Task<JsonResult> HobiVeIlgiAlanlariniKaydetGuncelle
                          (List<HobilerVM> hobiler, List<IlgiAlanlarVM> ilgiAlanlar) 

Lastly, I just make sure it's an array of objects to make sure it will bind nicely on your list of models:

        var hobiler = [{
            id: 1,
            value: 'My Value'
        }];
            
        var ilgiAlanlar = [{
            id: 1,
            value: 'MyValue'
        }];

       $.ajax({
            url: '@Url.Action("HobiVeIlgiAlanlariniKaydetGuncelle", "Kullanici")',
            type: "POST",
            contentType: 'application/json; charset=UTF-8',
            dataType: 'json',
            data: JSON.stringify({ hobiler : hobiler, ilgiAlanlar : ilgiAlanlar }),
            success: function (response) { }
        });