Blazor InputFile doesn't notice user cancellation

[MarvinKlein1508]

Describe the bug

I have an InputFile component and upload a file with it. The event OnChange gets raised fine. Now I click again on the browse button to change my uploaded document(s) and click on cancel. The component says nothing is selected now but the event doesn't raise again. So how should I detect that the user has deleted his/her upload?

To Reproduce

Consider the following code which writes the file to an Directory called Uploads.

<InputFile OnChange="OnInputFileChange" class="form-control" accept="application/pdf" />
@code 
{
	private async Task OnInputFileChange(InputFileChangeEventArgs e)
	{
		string path = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Uploads");
		string filename = Path.Combine(path, e.File.Name);

		if (!Directory.Exists(path))
		{
			Directory.CreateDirectory(path);
		}

		byte[] buffer = new byte[e.File.Size];
		await e.File.OpenReadStream().ReadAsync(buffer);

		await File.WriteAllBytesAsync(filename, buffer);
	}
}

Without detection for deletion I am not able to do validation. Consider my model for the input has a string which stores the path to the uploaded file which is being set within this method. So the user clicks on the button again and cancels the operation.
Because a cancel i snot recognized, I would still have my string in my model set to the file, the user has uploaded before. In addtion this results in unnesscary files on the server, which could have been easily removed if there was any way to detect user cancellation.

Further technical details

• ASP.NET Core version 5.0.2
• VS Studio 2019 - 16.8.4
  .NET SDK (gemäß "global.json"):
  Version: 5.0.200-preview.20601.7
  Commit: b3b934bbf2

Laufzeitumgebung:
OS Name: Windows
OS Version: 10.0.19042
OS Platform: Windows
RID: win10-x64
Base Path: C:\Program Files\dotnet\sdk\5.0.200-preview.20601.7\

Host (useful for support):
Version: 5.0.2
Commit: cb5f173b96

.NET SDKs installed:
3.1.400-preview-015203 [C:\Program Files\dotnet\sdk]
5.0.100-rc.1.20452.10 [C:\Program Files\dotnet\sdk]
5.0.100 [C:\Program Files\dotnet\sdk]
5.0.102 [C:\Program Files\dotnet\sdk]
5.0.200-preview.20601.7 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.All 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.24 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.24 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.0-rc.1.20451.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.24 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.0-rc.1.20451.14 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 3.1.11 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.0-rc.1.20452.2 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.2 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET runtimes or SDKs:
https://aka.ms/dotnet-download

Thanks for contacting us.
We're moving this issue to the Next sprint planning milestone for future evaluation / consideration. We will evaluate the request when we are planning the work for the next milestone. To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.

[DjeeBay]

Same here.

The thing is when cancelling the onChange event is not triggered by the browser itself.
As InputFile doesn't come with a solution, we have to find a workaround like adding a "clear button" and display file(s) data correctly (because when cancelling we still have the data).

You also can find JS workarounds.

Would be great if the InputFile component has the feature.

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.