public extern static Int32 GetThemeTextExtent(IntPtr hTheme, IntPtr hdc, int iPartId, int iStateId, String text, int textLength, UInt32 textFlags, ref RECT boundingRect, out RECT extentRect);

public extern static Int32 GetThemeTextExtent(IntPtr hTheme, IntPtr hdc, int iPartId, int iStateId, String text, int textLength, UInt32 textFlags, int boundingRect, out RECT extentRect);

Declare Function GetThemeTextExtent Lib "uxtheme.dll" (ByVal hTheme As IntPtr, ByVal hdcAs IntPtr, _