Asp.net core model doesn't bind from form

Question

I catch post request from 3rd-side static page (generated by Adobe Muse) and handle it with MVC action.

Answer 1

I had the same problem and I want to share what happened in my case and how I got the solution. Perhaps, someone may find it useful to know.

My context was ASP.NET Core 3.1 Razor pages. I had a handler as

public async Task OnPostLogin([FromForm] LoginInput loginData)
{
  
}

and also I had a property in my ViewModel as

  public LoginInput LoginInput { get; set; }

And in my Razor page, I have used the form like this:

 

 

 .....
 
        

So, notice that, in my form, I used the property LoginInput.UserNameOrEmail, but in my handler's parameter, I used the parameter name loginData. How will the ASP.NET Core know that, this LoginInput.UserNameOrEmail is actually loginData.UserNameOrEmail. It can't, right? Therefore, it did not bind my form data.

Then, when I renamed my ViewModel property "LoginInput" to the same name as the handler parameter, like this:

public LoginInput LoginData { get; set; }

The ASP.NET Core then found that the form data was matching the parameter name and then it started to bind properly. My problem was solved.