c# - How to enable button in WPF when task is done

Question

I have a button, click it to start a task and disable the button, when the task is completed, I want to enable this button. Please give me any idea, concept or code to make it easy for me to understand.

my code is below:

In xaml:

<Button Name="myButton" Content="START" Click="ButtonStartClick" />

In xaml.cs:

 private void ButtonStartClick(object sender, RoutedEventArgs e)
 {
     RunTask();
     myButton.IsEnabled = false;
 }

In viewModel.cs:

     private void OnTaskCompleted(string result)
     {
          //how to enable myButton
     }

Answer 1

Here is a first very naive approach, without MVVM

 private async void ButtonStartClick(object sender, RoutedEventArgs e)
 {
     myButton.IsEnabled = false;
     await RunTask();
     myButton.IsEnabled = true;
 }

where RunTask is declared like this:

 private async Task RunTask()
 {
     // await some other awaitable method(s)
 }

If you have a long running task that isn't awaitable, you may run it by Task.Run like this:

private async Task RunTask()
{
    await Task.Run(() =>
    {
        // do somthing here
    });
}