Cancel document viewing in ASP.NET Core

GroupDocs.Viewer Product Family
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1

Hi,

Is there any way to cancel document rendering in ASP.NET Core?
Cancel rendering | Documentation (groupdocs.com)

For example if there’s issue in the document, and we’d like to cancel it within IFileStorage.ReadFileAsync (or if there’s any other means).

Thank you.

2

@Bipo

Can you please clarify if you’re asking about GroupDocs.Viewer-for-.NET-UI?

3

Hi Vladimir,

Yes, correct.

4

@Bipo

Cancellation is not implemented in GroupDocs.Viewer-for-.NET-UI. Cancelling tasks typically implemented by passing CancellationToken.

Do you expect to have a method that accepts CancellationToken as a parameter?

5

Hi Vladimir,

Basically our scenario is like this: the document file is fetched from external API (this happens in IFileStorage.ReadFileAsync). There could be error or exception from this fetching. So we would like to render our custom message and view, instead of rendering GroupDoc Viewer view.
Please advise if this can be done.

Thank you.

6

@Bipo

Thank you for the clarification. We’ll take a look and update you.

7

@Bipo

At the moment the client app handles all the unsuccessful responses and shows a modal with the error message that comes in response. Even if you return redirect it will be handled but you won’t be redirected. We’ll consider implementing error handling in a such way so the users can manage the client app behavior.

8

@Bipo

The feature to show custom error message was added in GroupDocs.Viewer.UI 8.0.3.

By default, when the API responds with an error code, a popup displaying the exception message is automatically shown.

To override this behavior, you can implement the IErrorMessageProvider interface to log errors or return a custom error message.

Here’s an example of a custom error message provider implementation:

using GroupDocs.Viewer.UI.Api;

//...

public class MyErrorMessageProvider : IErrorMessageProvider
{
    public string GetErrorMessage(Exception exception, ErrorContext context)
    {
        return "This is my custom error message...";
    }
}

To register the custom error message provider:

using GroupDocs.Viewer.UI.Api;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddSingleton<IErrorMessageProvider, MyErrorMessageProvider>();

The screenshot below shows an error popup with a custom error message:

custom-error-message.png1917×1137 64.2 KB

Have a nice day!