public static extern bool WTSVirtualChannelQuery(IntPtr hChannelHandle, WTS_VIRTUAL_CLASS virtualClass, out IntPtr ppBuffer, out int pBytesReturned);
public static extern bool WTSVirtualChannelQuery( WtsVitrualChannelSafeHandle hChannelHandle, WTS_VIRTUAL_CLASS WtsVirtualClass, out WtsAllocSafeHandle ppBuffer, out int cBytesReturned );
public static extern Boolean WTSVirtualChannelQuery( IntPtr hChannelHandle, WTS_VIRTUAL_CLASS cls, out IntPtr ppBuffer, out UInt32 pBytesReturned);