如何动态加载和卸载本机DLL文件？

[DllImport(\"kernel32.dll\", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr LoadLibrary(string libname);

[DllImport(\"kernel32.dll\", CharSet = CharSet.Auto)]
private static extern bool FreeLibrary(IntPtr hModule);

//Load
IntPtr Handle = LoadLibrary(fileName);
if (Handle == IntPtr.Zero)
{
     int errorCode = Marshal.GetLastWin32Error();
     throw new Exception(string.Format(\"Failed to load library (ErrorCode: {0})\",errorCode));
}

//Free
if(Handle != IntPtr.Zero)
        FreeLibrary(Handle);

GetProcAddress

[DllImport(\"kernel32.dll\", CharSet = CharSet.Ansi)]
private static extern IntPtr GetProcAddress(IntPtr hModule, string lpProcName); 


IntPtr funcaddr = GetProcAddress(Handle,functionName);
YourFunctionDelegate function = Marshal.GetDelegateForFunctionPointer(funcaddr,typeof(YourFunctionDelegate )) as YourFunctionDelegate ;
function.Invoke(pass here your parameters);

  [DllImport(\"powrprof.dll\")]
  static extern bool IsPwrHibernateAllowed();

  [DllImport(\"kernel32.dll\")]
  static extern bool FreeLibrary(IntPtr hModule);

  [DllImport(\"kernel32.dll\")]
  static extern bool LoadLibraryA(string hModule);

  [DllImport(\"kernel32.dll\")]
  static extern bool GetModuleHandleExA(int dwFlags, string ModuleName, ref IntPtr phModule);

  static void Main(string[] args)
  {
        Console.WriteLine(\"Is Power Hibernate Allowed? \" + DoIsPwrHibernateAllowed());
        Console.WriteLine(\"Press any key to continue...\");
        Console.ReadKey();
  }

  private static bool DoIsPwrHibernateAllowed()
  {
        LoadLibraryA(\"powrprof.dll\");
        var result = IsPwrHibernateAllowed();
        var hMod = IntPtr.Zero;
        if (GetModuleHandleExA(0, \"powrprof\", ref hMod))
        {
            while (FreeLibrary(hMod))
            { }
        }
        return result;
  }