public extern static Int32 GetThemeBackgroundExtent(IntPtr hTheme, IntPtr hdc, int iPartId, int iStateId, ref RECT pRect, ref RECT pClipRect);

Declare Function GetThemeBackgroundExtent Lib "uxtheme.dll" (TODO) As TODO

Public Shared Function GetThemeBackgroundExtent(hTheme As IntPtr, hdc As IntPtr, iPartId As Integer, iStateId As Integer, ByRef pRect As RECT, ByRef pClipRect As RECT) As Int32