///<summary>Snaps the child window to the top level owner window, relative to the hWndSnap window. As
///the top level owner window is moved, resized, minimized or maximized, the child window moves too.</summary>
///<param name="child">The control that is automtically moved, e.g. a ToolStripDropDown window.</param>
///<param name="hWndTopLevel">A handle to a top-level window, e.g. a Form control's Handle.</param>
///<param name="hWndParent">A handle to a control that child window is relatively positioned, e.g. a TextBox or ComoBox.</param>
///<param name="snapPoint">Parameters that specify the X and Y location.</param>
public static void SnapWindow(this Control child, IntPtr hWndParent, IntPtr hWndTopLevel, SnapPoint snapPoint) {
if (child.IsHandleCreated)
SetOwner(child.Handle, hWndParent, hWndTopLevel, snapPoint);
else {
child.HandleCreated += delegate {
SetOwner(child.Handle, hWndParent, hWndTopLevel, snapPoint);
};
}
}
public static void SetOwner(IntPtr hWndChild, IntPtr hWndParent, IntPtr hWndTopLevel, SnapPoint snapPoint) {
Data d = (Data) htData[hWndChild];
if (d != null) {
d.nwOwner.ReleaseHandle();
if (hWndTopLevel != IntPtr.Zero)
d.nwOwner = new OwnerNW(hWndTopLevel, d);
else {
d.nwChild.ReleaseHandle();
htData.Remove(hWndChild);
}
}
else {
if (hWndTopLevel == IntPtr.Zero)
return;
d = new Data(snapPoint, hWndChild, hWndTopLevel, hWndParent);
htData[hWndChild] = d;
}
}
public Data(SnapPoint snapPoint, IntPtr hWndChild, IntPtr hWndOwner, IntPtr hWndSnap) {
this.snapPoint = snapPoint;
SnapHandle = hWndSnap;
nwChild = new ChildNW(hWndChild, this);
nwOwner = new OwnerNW(hWndOwner, this);
}