C#

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Popup popup = new Popup();<br />
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// Get bounds of the screen on which this Application is located<br />
Rectangle screenBounds = Screen.GetBounds(this.Location);<br />
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// Get scaling factor for font used (will be 1 if using small fonts, 96 fpi)<br />
float scaleY = Form.GetAutoScaleSize(this.Font).Height / 13.0f;<br />
float scaleX = Form.GetAutoScaleSize(this.Font).Width / 5.0f;<br />
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// Get screen coordinates of button that opens popup<br />
Point ButtonLocation = ((Control)sender).PointToScreen(Point.Empty);<br />
int x = ButtonLocation.X;<br />
int y = ButtonLocation.Y;<br />
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if( screenBounds.Bottom < (y+popup.Height) )	//Open popup up instead of down<br />
{<br />
        //make sure the whole of the popup fits on screen<br />
	if( eventButtonLocation.Y < popup.Height )<br />
		popup.Height = eventButtonLocation.Y;	<br />
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	y = (eventButtonLocation.Y - popup.Height + eventLabel.Height);<br />
}<br />
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if(screenBounds.Right < (x + popup.Width) )	//Open to left instead of right<br />
	x = x - popup.Width + ((Control)sender).Width;<br />
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// Set location of popup<br />
popup.Location = new Point(x,y);<br />
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// Add event handler<br />
popup.Closed += PopupClosedEventHandler;<br />
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// Display it<br />
popup.Show();<br />