Nsryjdtyk

I defined a model look like this

public class X { 

int a;

MyClass b;

}

and I have an action look like this

public IActionResult Test(X x){}

now when user submit data I want to manipulate that data and then assign it to b.
how can I do it?

You didn't provide the detailed explanation such as how you want to submit data , suppose you have a book model class that contains a child Author property :

    public class Book

    {

       public int id { get; set; }



       public string name { get; set; }



       public Author author { get; set; }

    }





    public class Author {

        public int authorId { get; set; }



        public string authorName { get; set; }

    }

In your view , using Tag Helpers in forms , you can bind to Author.authorName :

@model Book



<form asp-controller="Home" asp-action="RegisterInput" method="post">

    BookID:  <input asp-for="id" /> <br />

    BookName: <input asp-for="name" /><br />



    AuthorID:  <input asp-for="author.authorId" /> <br />

    AuthorName: <input asp-for="author.authorName" /><br />

    <button type="submit">Register</button>

</form>

In controller , you will find the input values will automatically bind to related properties :

    [HttpPost]

    [ValidateAntiForgeryToken]

    public async Task<IActionResult> RegisterInput(Book book)

    {



        return View();

    }