Why is asp-route-id not working in my form post?

Question

I have asp-route-id working in one instance:

It works from an anchor tag like this:

<a id="editModal" data-toggle="modal" data-target="#modal_box"
    class="btn btn-sm btn-primary"
    asp-action="Edit" asp-route-id="@user.Id">Edit</a>

and is received like this:

public async Task<PartialViewResult> DeleteConfirm(string Id) =>
        PartialView("_DeleteConfirm", await _userManager.FindByIdAsync(Id));

This method receives the correct id.

The next example has the route id in the form tag like this:

<div class="modal-footer">
    <form asp-controller="Account" asp-action="Delete" asp-route-id="@Model.Id" method="post">
        <button type="submit" class="btn btn-primary"
           asp-action="Delete">Yes - Delete this User</button>
        <a asp-action="Index" class="btn btn-default">Cancel</a>
    </form>
</div>

and I am trying to receive the Id here:

    [HttpPost]
    public async Task<IActionResult> Delete(string Id)
    {
        AppUser user = await _userManager.FindByIdAsync(Id);
        if (user != null)
        {
            IdentityResult result = await _userManager.DeleteAsync(user);
            if (result.Succeeded)
            {
                return RedirectToAction("Index");
            }
            else
            {
                AddErrorsFromResult(result);
            }
        }
        else
        {
            ModelState.AddModelError("", "User Not Found");
        }
        return View("Index", _userManager.Users);
    }

But in this case the parameter is coming in null.

It should work from the from tag. I got this from the first Identity Chapter in Adam Freemans APress MVC Core book and it worked when I typed it in for that example.

Kibe

Did you check the form that was generated in the HTML? Either the action URL there is wrong or model binding is not working. Typically the parameter would be called id instead of Id. – Oliana

good call on naming convention. Thanks. Still trying to fix though. – Kibe

Answer 1

You must change the asp-route-id to asp-route-Id because after "asp-router-" you must put the name of the parameter that you are going to send to the method.

Embodiment

Man, this gets me every time. everything after asp-route- has to match casing exactly to what your route parameter is. – Speakeasy

Answer 2

I inspected the form tag in response to junnas' comments.

It looked like this:

<form method="post" action="/Account/Delete/5066a97b-7eb4-4e1d-889b-3f3450adc1d6">
        <button type="submit" class="btn btn-primary" formaction="/Account/Delete">Yes - Delete this User</button>
        <a class="btn btn-default" href="/Account">Cancel</a>
    <input name="__RequestVerificationToken" type="hidden" value="CfDJ8At6yzynfgJHstUkF5jJTYgHHX0on9ajBa9NfD60YGbM7aRhKjDQUGkh4gPAMkwwOsnqUtDxSx87MnUvbxcefB7tGX1v0Xi38h_SoL_iakiFdJSpUbymp4tsr-cMFNK3kwYx7o42OumLkFbvFn1Nyun_8LDc0mmOvGN5LeeHiIq84cSJCaaiyR_2talw6Dpcvw" /></form>

Notice the extra formaction="/Account/Delete"> right on the button in addition to the form action.

I had an extra asp-route-id left over on a button I had changed over from an anchor.

I had to take it off the button here:

<form asp-controller="Account" asp-action="Delete" asp-route-id="@Model.Id" method="post">
        <button asp-route-id="@Model.Id" type="submit" class="btn btn-primary">Yes - Delete this User</button>
        <a asp-action="Index" class="btn btn-default">Cancel</a>
    </form>

and make the button like this:

Yes - Delete this User

Kibe