Moving event handling to ViewModel
Suppose that when a Button is pressed, we want to handle that fact in the ViewModel, as is preferred by the Model-View-ViewModel (MVVM) pattern. However, one of the things we want to do, in response to that Button press, is to show a ProgressBar.
Handling things in ViewModel gets tricky when we want to interact with the user interface (UI). However, it can be done in a number of ways. Let’s modify the Submit button, remove its Clicked event and add a command:
<Button
BackgroundColor="Gray"
Command="{Binding SubmitCommand}"
Margin="5"
Text="Submit" />
We’ll create RelayCommand in ViewModel to handle the Submit Command:
[RelayCommand]
private async void Submit()
{
for (var i = 0.0; i < 1.0; i += 0.1)
{
await LoginPage.LoginProgressBar...