How to print a unicode at predefined position?(use WritePrinter)

Question

In the DirectPrint sample code: ...... [ DllImport( "winspool.drv",CharSet=CharSet.Ansi,ExactSpelling=true, CallingConvention=CallingConvention.StdCall)] public static extern long WritePrinter(IntPtr hPrinter,string data, int buf,ref int pcWritten); ...... when I replaced "Ansi" with "Unicode" and put some unicode word into 'data', unreadable letters were prited . Can anybody help me settle this problem ? Thanks a lot !