Accessing UI controls in Task.Run with async/await on WinForms

Question

I have the following code in a WinForms application with one button and one label:

using System;
using System.IO;
using System.Threading.Tasks;
using System.         


        

Answer 1

Why do you use Task.Run? that start a new worker thread (cpu bound), and it causes your problem.

you should probably just do that:

    private async Task Run()
    {
        await File.AppendText("temp.dat").WriteAsync("a");
        label1.Text = "test";    
    }

await ensure you will continue on the same context except if you use .ConfigureAwait(false);