CODEWITHSUNDEEP
c#wpf
JokerMartini
JokerMartini

Reputation: 6147

Apply event to all controls of type

I have two questions here regarding a wpf C# project.

  1. What is this snippet doing? PreviewMouseMove += OnPreviewMouseMove; as seen in the code below. 
public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();

        PreviewMouseMove += OnPreviewMouseMove;
        PreviewMouseLeftButtonUp += OnPreviewMouseUp;
        MouseLeave += OnMouseLeave;
    }

    private void OnMouseLeave(object sender, MouseEventArgs e)
    {
        spinnerControl.StopDragCapture(null);
    }

    private void OnPreviewMouseUp(object sender, MouseButtonEventArgs e)
    {
        spinnerControl.StopDragCapture(e);
    }

    private void OnPreviewMouseMove(object sender, MouseEventArgs e)
    {

        spinnerControl.UpdateOnDragMove(e);
    }
}
  1. The main question here is, how can I essentially apply all these MouseEvents to each control of type in my window? I've already put together a function which finds all the controls of type in my window, thanks to SO. I'm just not clear on how to write up the actual function which assigns the event to the control. 
public partial class MainWindow : Window
{
    // Enumerate all the descendants of the visual object.
    public static IEnumerable<T> FindVisualChildren<T>(DependencyObject depObj) where T : DependencyObject
    {
        if (depObj != null)
        {
            for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
            {
                DependencyObject child = VisualTreeHelper.GetChild(depObj, i);
                if (child != null && child is T)
                {
                    yield return (T)child;
                }

                foreach (T childOfChild in FindVisualChildren<T>(child))
                {
                    yield return childOfChild;
                }
            }
        }
    }

    private void InitNumericSpinners()
    {
        foreach (NumericSpinnerControl spinner in FindVisualChildren<NumericSpinnerControl>(this))
        {
            // do something here
            // spinner (add OnMouseLeave event)
            // spinner (add OnPreviewMouseUp event)
            // spinner (add OnPreviewMouseMove event)
        }
    }

    private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        InitNumericSpinners();
    }
}

Upvotes: 0

Views: 200

Answers (1)

D Stanley
D Stanley

Reputation: 152556

What is this snippet doing?

It's assigning a handler to the window's PreviewMouseMove event

how can I essentially apply all these MouseEvents to each control of type in my window?

You already know how to find all of the controls - so just loop through and assign the handler:

    foreach (NumericSpinnerControl spinner in FindVisualChildren<NumericSpinnerControl>(this))
    {
        // do something here
        spinner.MouseLeave = OnMouseLeave;
        spinner.PreviewMouseUp = OnPreviewMouseUp;
        spinner.PreviewMouseMove = OnPreviewMouseMove;
    }

Note that you probably want to change spinnerControl to sender in your event handler to you're affecting the control that initiated the event rather than referencing a specific control.

Upvotes: 1

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