See also ImmGetConversionList function page

public static extern int ImmGetConversionList(

Declare Function ImmGetConversionList Lib "Imm32.dll" (TODO) As TODO

        int dwSize = ImmGetConversionList(hKL,hIMC,AText,IntPtr.Zero,0,GCL_REVERSECONVERSION);

            ImmGetConversionList(hKL,hIMC,AText,BufList,dwSize,GCL_REVERSECONVERSION);

See also ImmGetConversionList function page