我不能等待等待？

Question

Visual Studio complains on the following:

public RelayCommand SendRegistrationCommand { get; private set; }
public async void SendRegistration()
{
    HttpClient client = new HttpClient();
    var response = await client.GetStringAsync("url");

    // ... todo
}

Cannot await 'System.Threading.Tasks.Task<string>'

I thought I've done this before, GetStringAsync is not awaitable?

Answer 1

You're probably targeting .NET 4.0.

If you can, switch to .NET 4.5 which supports async/await semantics.

If you can't, consider using the Async Targeting Pack: https://www.nuget.org/packages/Microsoft.CompilerServices.AsyncTargetingPack

Edit

As per the comments, Microsoft.Bcl.Async should be used instead: https://www.nuget.org/packages/Microsoft.Bcl.Async

Answer 2

Ensure that client.GetStringAsync("url") is an async Task

private async Task GetStringAsync(string str)
{
}