视图中的控制器在编辑后不会更新视图模型

Question

I have the following form.

@model LoginVm
<form asp-controller="Sec" 
      asp-action="Authorize"
      asp-all-route-data="@Model.Querify" 
      method="post">
  Email:  <input asp-for="@Model.UserName" /> <br />
  Password: <input asp-for="@Model.Password" /><br />
  <button type="submit">Send</button>
</form>

The view model is like this.

public class LoginVm
{
  public string UserName { get; set; }
  public string Password { get; set; }
  public string ReturnUrl { get; set; }

  public IDictionary<string, string> Querify 
    => new Dictionary<string, string>
    {
      { "username", UserName },
      { "password", Password },
      { "returnurl", ReturnUrl }
    };
  }

However, in the receiving method shown below, only the values that are written to the view model before rendition are present. So, whatever I put in the view model prior to passing it into the view, it's there. Any changes I try to do to the model in the input boxes are lost.

[HttpPost]
public IActionResult Authorize(
  [FromQuery]string returnUrl, 
  [FromQuery]string userName, 
  [FromQuery] string password)
{ ... }

I though based on the docs that I bound the value from the input box to the fields in the model but apparently I have not. Not sure how to diagnose it further.

Answer 1

I think you might be binding the original data back due to the line:

      asp-all-route-data="@Model.Querify" 

I think this is sending the original model back to the controller as the parameters and ignores the ones in your form.

Remove that line and replace it with

 asp-route-returnurl="@Model.ReturnUrl"

Edit:

Updated based on comments.

Tested this as working, looks like the [FromQuery] is also an issue so replaced with just taking the viewmodel back.

Controller code:

  public IActionResult Sec()
    {
        var viewModel = new LoginVm();

        viewModel.ReturnUrl = "http://stackoverflow.com";
        return View(viewModel);
    }

    [HttpPost]
    public IActionResult Sec(LoginVm viewModel)
    {
       return Redirect(viewModel.ReturnUrl);
    }

ViewModel:

     public class LoginVm
{
    public string UserName { get; set; }
    public string Password { get; set; }
    public string ReturnUrl { get; set; }
}

View:

 @model LoginVm
<form asp-controller="Authorization"
  asp-action="Sec"   
asp-route-returnurl="@Model.ReturnUrl"
  method="post">
Email:  <input asp-for="@Model.UserName" /> <br />
Password: <input asp-for="@Model.Password" /><br />
<button type="submit">Send</button>
</form>