Relay Command can execute and a Task

Question

i want to start a task when a relay command is called, however i want to disable the button as long as that task is running

take this example

private         


        

Answer 1

I strongly recommend that you avoid new Task as well as Task.Factory.StartNew. The proper way to start an asynchronous task on a background thread is Task.Run.

You can create an asynchronous RelayCommand easily using this pattern:

private bool updateInProgress;
private ICommand update;
public ICommand Update
{
  get
  {
    if (update == null)
    {
      update = new RelayCommand(
          async () =>
          {
            updateInProgress = true;
            Update.RaiseCanExecuteChanged();

            await Task.Run(() => StartUpdate());

            updateInProgress = false;
            Update.RaiseCanExecuteChanged();
          },
          () => !updateInProgress);
    }
    return update;
  }
}