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Check if a target was not hit in WPF

Anonymous User 2476 14-Nov-2014

I'm using the code below to see when the mouse right button is clicked, if it hits a target (Drawing) or not.

Now If the mouse hits the target a message will be shown stating that we hit the target.

But where can I show a message that the target was NOT hit? VisualTreeHelper.HitTest() doesn't seem to return a value indicating that the target was hit or not.

private void OnMouseRightButtonUp(object sender, MouseButtonEventArgs e)
{
    var x = MousePos.RightDown.X;
    var y = MousePos.RightDown.Y;
    var hitRect = new Rect(x - 2, y - 2, 4, 4);
    var geom = new RectangleGeometry(hitRect);
    VisualTreeHelper.HitTest(Drawing,                         
null, 
                            
MyCallback, 
                            
new GeometryHitTestParameters(geom));
}
private HitTestResultBehavior MyCallback(HitTestResult result)
{
    MessageBox.Show("You hit the target");
    return HitTestResultBehavior.Stop;
}

wpf c# 
Updated on 15-Nov-2014
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1 Answers

Anonymous User

Anonymous User

15-Nov-2014

Have some class level flag to indicate whether hit is successful or not. Set the flag to true from MyCallback and show message based on that flag.

bool isTargetHit;    
private void OnMouseRightButtonUp(object sender, MouseButtonEventArgs e)
{
    isTargetHit = false;
    .......
    VisualTreeHelper.HitTest(Drawing, 
                             null, 
                             MyCallback, 
                             new GeometryHitTestParameters(geom));
 
    if(isTargetHit)
    {
        MessageBox.Show("You hit the target");
    }
    else
    {
        MessageBox.Show("You did not hit the target");
    } 
}
private HitTestResultBehavior MyCallback(HitTestResult result)
{
    isTargetHit = true;
    return HitTestResultBehavior.Stop;
}

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