问向MonthCalendar发送MCM_GETSELRANGE消息的P/Invoke签名是什么？

EN

using System;
using System.Runtime.InteropServices;

namespace GetSelRange
{
    class Program
    {
        static void Main(string[] args)
        {
            IntPtr targetWindowHandle = new IntPtr(68684130);
            SYSTEMTIME[] dateRange = new SYSTEMTIME[2];
            IntPtr success = SendMessage(targetWindowHandle, MCM_GETSELRANGE, IntPtr.Zero, dateRange);
        }

        #region Win32API

        const uint MCM_FIRST = 0x1000;
        const uint MCM_GETSELRANGE = MCM_FIRST + 5;

        [StructLayout(LayoutKind.Sequential)]
        private struct SYSTEMTIME
        {
            [MarshalAs(UnmanagedType.U2)]
            public ushort Year;
            [MarshalAs(UnmanagedType.U2)]
            public ushort Month;
            [MarshalAs(UnmanagedType.U2)]
            public ushort DayOfWeek;
            [MarshalAs(UnmanagedType.U2)]
            public ushort Day;
            [MarshalAs(UnmanagedType.U2)]
            public ushort Hour;
            [MarshalAs(UnmanagedType.U2)]
            public ushort Minute;
            [MarshalAs(UnmanagedType.U2)]
            public ushort Second;
            [MarshalAs(UnmanagedType.U2)]
            public ushort Milliseconds;
        }

        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, IntPtr wParam, SYSTEMTIME[] lParam);

        #endregion
    }
}