Blazor: add support for onclose event

[campersau]

Add support for onclose event

Similar to #24036

Description

Reference: https://developer.mozilla.org/en-US/docs/Web/API/HTMLDialogElement/close_event

There is also a cancel event for <dialog>, should it be added as well?

Fixes #50513

[ghost]

Thanks for your PR, @campersau. Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

[SteveSandersonMS]

This call shouldn't be needed, since the event dispatcher causes the equivalent to StateHasChanged implicitly anyway. Would be good to update this file so that the tests validate it works without explicitly calling this.

[SteveSandersonMS]

I'm just going to remove it now, because if it works and the tests pass, we can still merge this in time for .NET 8. If it misses the end-of-day deadline today, it will slip into .NET 9!

[campersau]

I just copied it from the ToggleEventComponent maybe there are more unnecessary StateHasChanged in other test components as well.

[SteveSandersonMS]

There is also a cancel event for , should it be added as well?

Ideally yes

[SteveSandersonMS]

I'll get this finalized in time for .NET 8, so need to close this PR in favor of #50727. Your commit will be preserved, though.

[campersau]

There is also a cancel event for , should it be added as well?

Ideally yes

Should I add it as well or are you going to add it in the other PR?

When you add both oncancel and onclose eventhandlers and hit the Escape key then both events will be called in this order oncancel, onclose.

[ghost]

Hi @campersau. It looks like you just commented on a closed PR. The team will most probably miss it. If you'd like to bring something important up to their attention, consider filing a new issue and add enough details to build context.

[SteveSandersonMS]

Should I add it as well or are you going to add it in the other PR?

I've added it in #50727