Adding asp-route-id to a submit button deactivates the asp-action of a form

[mauler2025]

The working example below

<form  asp-action="DeleteConfirmed">
     <input type="submit"  value="Delete"  />                    
</form>

public async Task<IActionResult> Delete(int id)
{
  // intentionally removed for simplicity 
}

[HttpPost]
public async Task<IActionResult> DeleteConfirmed(int id)
{
  // intentionally removed for simplicity 
}

no longer works if I add asp-route-id="1" as follows.

<form asp-action="DeleteConfirmed">
     <input type="submit" asp-route-id="1"  value="Delete"  />                    
</form>

public async Task<IActionResult> Delete(int id)
{
  // intentionally removed for simplicity 
}

[HttpPost]
public async Task<IActionResult> DeleteConfirmed(int id)
{
  // intentionally removed for simplicity 
}

To make it work again, I have to explicitly specify asp-action=DeleteConfirmed in the submit button as follows

<form asp-action="AnyTrivialString">
     <input type="submit" asp-route-id="1"  value="Delete"  asp-action="DeleteConfirmed" />                    
</form>

Note: A string assigned to asp-action of the form will be overridden by the submit button. As a result, the form asp-action becomes trivial.

Question

Is it a bug or a known feature?

Minimal Working Example

See my repo here

[mkArtakMSFT]

Thank you for filing this issue. In order for us to investigate this issue, please provide a minimalistic repro project that illustrates the problem.

[mkArtakMSFT]

Thanks @pstricks-fans.
@pranavkm can you please have a look at this? Thanks!

[mauler2025]

@mkArtakMSFT and @pranavkm :

I have simplified the project and I found that the presence of asp-route-id causes this issue.

[mauler2025]

I remove the area to shrink the surface area on which you have to probe.

[pranavkm]

@pstricks-fans the scenarios you listed make sense:

<!-- Working -->
@*<form asp-action="AnyTrivialString">
    <input type="submit" asp-route-id="1" asp-action="DeleteConfirmed" />
</form>*@


<!-- Not Working -->
<form asp-action="DeleteConfirmed">
    <input type="submit" asp-route-id="1" />
</form>

When you add an asp-route-id on a submit button, it independently determines the Action it would route to. It does not work in tandem with the values you specified in form. If you're attempting to post to two different actions from a single form, using the "working" sample would be the way go. Alternatively, specifying all the route values on the form tag would be the way to go:

<form asp-action="DeleteConfirmed" asp-route-id="1">
    <input type="submit" />
</form>