The data for the Splitter.SplitterMoving and SplitterMoved events is encapsulated by this class. You can retrieve the location of the top left of the Splitter with the SplitX and SplitY members , and the current mouse position (in the client coordinates of the splitters Parent window) with X and Y . public class SplitterEventArgs : EventArgs { // Public Constructors public SplitterEventArgs (int x , int y , int splitX , int splitY ); // Public Instance Properties public int SplitX {set; get; } public int SplitY {set; get; } public int X {get; } public int Y {get; } } HierarchySystem.Object System.EventArgs SplitterEventArgs Passed ToSplitter.{OnSplitterMoved() , OnSplitterMoving()} , SplitterEventHandler.{BeginInvoke() , Invoke()} |