Although DoIt() is executed on a remote computer, it is best to attach Completed event handler immediately. Otherwise, when the process completes, you might miss out on the callback.
You are correct. The two ways of calling DoIt are mutually exclusive.
If you have complicated logic, you may want to consider using the Bcl Async library. See this blog post.
Using async, your code will look like this:
// Note: you will need the OperationExtensions helper
public async void CallDoItAndDosomething()
{
this.BusyIndicator.IsBusy = true;
await context.DoIt(0).AsTask();
this.BusyIndicator.IsBusy = false;
}
public static class OperationExtensions
{
public static Task<T> AsTask<T>(this T operation)
where T : OperationBase
{
TaskCompletionSource<T> tcs =
new TaskCompletionSource<T>(operation.UserState);
operation.Completed += (sender, e) =>
{
if (operation.HasError && !operation.IsErrorHandled)
{
tcs.TrySetException(operation.Error);
operation.MarkErrorAsHandled();
}
else if (operation.IsCanceled)
{
tcs.TrySetCanceled();
}
else
{
tcs.TrySetResult(operation);
}
};
return tcs.Task;
}
}