AsyncAwaitBestPractices

Extensions for System.Threading.Tasks.Task, inspired by John Thiriet's blog posts: Removing Async Void and MVVM - Going Async With AsyncCommand.

• AsyncAwaitBestPractices
  • An extension method to safely fire-and-forget a Task:
    • SafeFireAndForget
  • Usage instructions below
• AsyncAwaitBestPractices.MVVM
  • Allows for Task to safely be used asynchronously with ICommand:
    • IAsyncCommand : ICommand
    • AsyncCommand : IAsyncCommand
    • AsyncCommand<T> : IAsyncCommand
  • Usage instructions below

Setup

AsyncAwaitBestPractices

• Available on NuGet: https://www.nuget.org/packages/AsyncAwaitBestPractices/
• Add to any project supporting .NET Standard 1.0

AsyncAwaitBestPractices.MVVM

• Available on NuGet: https://www.nuget.org/packages/AsyncAwaitBestPractices.MVVM/
• Add to any project supporting .NET Standard 2.0

Usage

AsyncAwaitBestPractices

An extension method to safely fire-and-forget a Task:

• SafeFireAndForget

void HandleButtonTapped(object sender, EventArgs e)
{
    // Allows the async Task method to safely run on a different thread while not awaiting its completion
    ExampleAsyncMethod().SafeFireAndForget();
    
    // HandleButtonTapped continues execution here while `ExampleAsyncMethod()` is running on a different thread
    // ...
}

async Task ExampleAsyncMethod()
{
    await Task.Delay(1000);
}

AsyncAwaitBestPractices.MVVM

Allows for Task to safely be used asynchronously with ICommand:

• AsyncCommand<T> : IAsyncCommand
• AsyncCommand : IAsyncCommand
• IAsyncCommand : ICommand

public class ExampleClass
{
    public ExampleClass()
    {
        ExampleAsyncCommand = new AsyncCommand(ExampleAsyncMethod);
        ExampleAsyncIntCommand = new AsyncCommand<int>(ExampleAsyncMethodWithIntParameter);
        ExampleAsyncExceptionCommand = new AsyncCommand(ExampleAsyncMethodWithException, onException: ex => Console.WriteLine(ex.Message));
        ExampleAsyncCommandNotReturningToTheCallingThread = new AsyncCommand(ExampleAsyncMethod, continueOnCapturedContext: false);
    }
    
    public IAsyncCommand ExampleAsyncCommand { get; }
    public IAsyncCommand ExampleAsyncIntCommand { get; }
    public IAsyncCommand ExampleAsyncExceptionCommand { get; }
    public IAsyncCommand ExampleAsyncCommandNotReturningToTheCallingThread { get; }

    async Task ExampleAsyncMethod()
    {
        await Task.Delay(1000);
    }
  
    async Task ExampleAsyncMethodWithIntParameter(int parameter)
    {
        await Task.Delay(parameter);
    }
    
    async Task ExampleAsyncMethodWithException()
    {
        await Task.Delay(1000);
        throw new Exception();
    }
    
    void ExecuteCommands()
    {
        ExampleAsyncCommand.Execute(null);
        ExampleAsyncIntCommand.Execute(1000);
        ExampleAsyncExceptionCommand.Execute(null);
        ExampleAsyncCommandNotReturningToTheCallingThread.Execute(null);
    }
}