CODEWITHSUNDEEP
c#restpolly
doorman
doorman

Reputation: 16959

Throwing specific exception when using Polly

I am using polly policy for retry attempts in the following way:

results = await Policy
                .Handle<WebException>()
                .WaitAndRetryAsync
                (
                    retryCount: 5,
                    sleepDurationProvider: retryAttempt => TimeSpan.FromSeconds(Math.Pow(2, retryAttempt))
                )
                .ExecuteAsync(async () => await task.Invoke());

I am using the AsyncErrorHandler to handle all the web exceptions:

public static class AsyncErrorHandler
{
    public static void HandleException(Exception ex)
    {
        Debug.WriteLine(ex.Message);
    }
}

However some of the expections I would like to throw up to the GUI. With this code in place how can I prevent handling of a specific exception and instead throw it to the GUI?

[UPDATE] If I throw a specific exception inside the HandleException function I receive an Unhandled Error Message dialog in Visual Studio.

Upvotes: 3

Views: 3636

Answers (1)

Joshua Smith
Joshua Smith

Reputation: 132

Implement it differently to only throw errors on the ones you want displayed to a user, then catch those you want to throw and do what you want with their contents (either show to user or not).

try
{
      results = await Policy
            .Handle<WebException>()
            .WaitAndRetryAsync
            (
                retryCount: 5,
                sleepDurationProvider: retryAttempt =>  TimeSpan.FromSeconds(Math.Pow(2, retryAttempt))
            )
            .ExecuteAsync(async () => await task.Invoke());
}

catch (ExceptionToThrowToUser ex)
{
    MessageBox.Show(ex.Message);
}


public static class AsyncErrorHandler
{
    public static void HandleException(Exception ex)
    {
        if (ex is ExceptionToThrowToUser)
        {
           throw;               
        }
        else
            Debug.WriteLine(ex.Message);
    }
}

Editted for update.

For help handling errors: Best practices for catching and re-throwing .NET exceptions

Upvotes: 2

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