https://ryuanerin.kr/post/2016-03-05-createwindows

NativeMethods.cs

static class NativeMethods
{
    [DllImport("user32.dll")]
    [return: MarshalAs(UnmanagedType.Bool)]
    public static extern bool PeekMessage(
        [In] ref MSG lpMsg,
        IntPtr hwnd,
        uint wMsgFilterMin,
        uint wMsgFilterMax,
        uint wRemoveMsg);
    
    [DllImport("user32.dll")]
    public static extern bool TranslateMessage(
        [In] ref MSG lpMsg);
    
    [DllImport("user32.dll")]
    public static extern IntPtr DispatchMessage(
        [In] ref MSG lpmsg);
    
    [StructLayout(LayoutKind.Sequential)]
    public struct MSG
    {
        public int      hwnd;
        public int      message;
        public int      wParam;
        public int      lParam;
        public int      time;
        public POINTAPI pt;
    }
    
    [StructLayout(LayoutKind.Sequential)]
    public struct POINTAPI
    {
        public int x;
        public int y;
    }
}

PeekMessage.cs

var msg = new NativeMethods.MSG();

while (true)
{
    if (NativeMethods.PeekMessage(ref msg, IntPtr.Zero, 0, 0, NativeMethods.PM_REMOVE))
    {
        NativeMethods.TranslateMessage(ref msg);
        NativeMethods.DispatchMessage(ref msg);
    }
}