/// <summary>
/// Adds the commands to the popup and creates the machting wait handles.
/// </summary>
private void AddCommandsToPopup()
{
// In case no commmand is set, add a continue command without an action.
if (CommandList.Count == 0)
{
CommandList.Add(new UICommand("Continue"));
}
// Remove exiting buttons in case ShowAsync was called more than once.
ControlStackPanel.Children.Clear();
// Create the command delegate used when a button is pressed
DelegateCommand <ManualResetEvent> commandDelegate = new DelegateCommand <ManualResetEvent>(OnButtonPressed);
// Iterate over the list of commands.
foreach (IUICommand command in CommandList)
{
// Create a new wait handle for the command
ManualResetEvent waitHandle = new ManualResetEvent(false);
// Add it to the list.
WaitHandleList.Add(waitHandle);
// Create the button and attach the wait handle.
Button button = new Button()
{
Command = commandDelegate,
CommandParameter = waitHandle,
Content = command.Label,
Style = (Style)Application.Current.Resources["ButtonStyle"]
};
// Add the button to the popup
ControlStackPanel.Children.Add(button);
}
}
/// <summary>
/// Begins an asynchronous operation showing a dialog.
/// </summary>
/// <returns>Nothing.</returns>
public async Task <IUICommand> ShowAsync()
{
// Add all commands to the command bar and create the matching wait handles.
AddCommandsToPopup();
// Keeps the index of the signaled wait handle.
int signaledHandle = -1;
// Find the control currently having the focus
Control focusedControl = FocusManager.GetFocusedElement() as Control;
// Start the thread to wait for user input.
Task waitForUserInputTask = Task.Run(() =>
{
// Wait for a handle to be signaled.
signaledHandle = ManualResetEvent.WaitAny(WaitHandleList.ToArray());
});
// Open the message box with a popup.
Popup popup = PopupHelper.CreateFullScreenWithChild(this);
// Set the focus on the defined button
if (FocusCommandIndex >= 0 &&
FocusCommandIndex < CommandList.Count)
{
((Button)(ControlStackPanel.Children[FocusCommandIndex])).Focus(FocusState.Programmatic);
}
// Wait for the wait thread to finish (one of the events to be signaled)
await Task.WhenAny(new Task[] { waitForUserInputTask });
// Free all wait handles.
while (WaitHandleList.Count > 0)
{
WaitHandleList[0].Dispose();
WaitHandleList.RemoveAt(0);
}
try
{
// Invoke the event handler of the selected command in case it is defined.
if (CommandList[signaledHandle].Invoked != null)
{
CommandList[signaledHandle].Invoked.Invoke(CommandList[signaledHandle]);
}
}
catch (Exception)
{
// re-throw any exception caused by the event handler.
throw;
}
finally
{
// Make sure the popup will be closed.
popup.IsOpen = false;
// Release the message box from the popup
popup.Child = null;
// Reset the focus
if (focusedControl != null)
{
focusedControl.Focus(FocusState.Programmatic);
}
}
// Return the selected command
return(CommandList[signaledHandle]);
}
