Blazor client-side Application level exception handling

Question

How to globally handle application level exceptions for client-side Blazor apps?

Answer 1

You can create a singleton service that handles the WriteLine event. This will be fired only on errors thanks to Console.SetError(this);

public class ExceptionNotificationService : TextWriter
{
    private TextWriter _decorated;
    public override Encoding Encoding => Encoding.UTF8;

    public event EventHandler<string> OnException;

    public ExceptionNotificationService()
    {
        _decorated = Console.Error;
        Console.SetError(this);
    }

    public override void WriteLine(string value)
    {
        OnException?.Invoke(this, value);

        _decorated.WriteLine(value);
    }
}

You then add it to the Startup.cs file in the ConfigureServices function:

services.AddSingleton<ExceptionNotificationService>();

To use it you just subscribe to the OnException event in your main view.

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