C ＃ introducing WinAPI to pass the character set of Chinese string parameters

C# Can pass DllImport introduce WinAPI. The complete introduction statement contains dll file name （ route ）,CharSet Character set ,EntryPoint Function entrance ,SetLastError Whether to set before calling WinAPI function SetLastError value

   [DllImport("user32.dll", CharSet = CharSet.Auto, EntryPoint = "MessageBox", SetLastError=false)]    
   public static extern int MyMessageBox(IntPtr hWnd, String text, String caption, uint type); 

CharSet The default value is not CharSet.Auto, It is CharSet.Ansi

WinAPI The character set used in the string parameter of the function is in different versions Windows The system is not unified ,XP Previous systems were usually Ansi Character set ,Windows7 and NT System is Unicode Character set . Usually use CharSet.Auto Parameters , It's always right to let the system choose automatically （ But I don't know why the default parameter is not CharSet.Auto）, Unless you specify to call AbcW Wide character set or AbcA Function version of narrow character set .
If you don't specify CharSet, System default use CharSet.Ansi, If you pass a Chinese string , The probability is that the call will fail , Or garbled .