public async Task <T> ShowDialogAsync <T>(DialogScreen <T> dialogScreen)
{
var view = GetViewForDialogScreen(dialogScreen);
void OnDialogOpened(object?openSender, DialogOpenedEventArgs openArgs)
{
void OnScreenClosed(object?closeSender, EventArgs args)
{
openArgs.Session.Close();
dialogScreen.Closed -= OnScreenClosed;
}
dialogScreen.Closed += OnScreenClosed;
}
await DialogHost.Show(view, OnDialogOpened);
return(dialogScreen.DialogResult);
}
public async Task <T> ShowDialogAsync <T>(DialogScreen <T> dialogScreen)
{
// Get the view that renders this viewmodel
var view = _viewManager.CreateAndBindViewForModelIfNecessary(dialogScreen);
// Set up event routing that will close the view when called from viewmodel
DialogOpenedEventHandler onDialogOpened = (sender, e) =>
{
// Delegate to close the dialog and unregister event handler
void OnScreenClosed(object o, CloseEventArgs args)
{
e.Session.Close();
dialogScreen.Closed -= OnScreenClosed;
}
dialogScreen.Closed += OnScreenClosed;
};
// Show view
await DialogHost.Show(view, onDialogOpened);
// Return the result
return(dialogScreen.DialogResult);
}
public UIElement GetViewForDialogScreen <T>(DialogScreen <T> dialogScreen)
{
var dialogScreenType = dialogScreen.GetType();
if (_dialogScreenViewCache.TryGetValue(dialogScreenType, out var cachedView))
{
_viewManager.BindViewToModel(cachedView, dialogScreen);
return(cachedView);
}
else
{
var view = _viewManager.CreateAndBindViewForModelIfNecessary(dialogScreen);
// This warms up the view and triggers all bindings.
// We need to do this, as the view may have nested model-bound ContentControls
// which take a very long time to load.
// By pre-loading them as early as possible, we avoid doing it when the dialog
// actually pops up, which improves user experience.
// Ideally, the whole view cache should be populated at application startup.
view.Arrange(new Rect(0, 0, 500, 500));
return(_dialogScreenViewCache[dialogScreenType] = view);
}
}
