I found the solution..
Thanks everyone..
private void treeList1_Click(object sender, System.EventArgs e) {
DevExpress.XtraTreeList.TreeList tree = sender as DevExpress.XtraTreeList.TreeList;
DevExpress.XtraTreeList.TreeListHitInfo info = tree.CalcHitInfo(tree.PointToClient(MousePosition));
if(info.HitInfoType == DevExpress.XtraTreeList.HitInfoType.Cell)
... // your code is here
}