C# 包装类

 /// <summary>
 /// 包装类
 /// </summary>
 public class CryptMath
 {
  //应用的DLL
  [DllImport("testDll.dll",CharSet=CharSet.Ansi)]

  public static extern void Crypt(
   //指针类型
   [MarshalAs(UnmanagedType.LPStr)]
   //参数
   ref string src,
   [MarshalAs(UnmanagedType.LPStr)]
   ref string key,
   [MarshalAs(UnmanagedType.LPStr)]
   ref String str   
   );

  [DllImport("testDll.dll",CharSet=CharSet.Unicode)]
  public static extern void DeCrypt(
   [MarshalAs(UnmanagedType.LPStr)]
   ref String src,
   [MarshalAs(UnmanagedType.LPStr)]
   ref String key,
   [MarshalAs(UnmanagedType.LPStr)]
   ref String crypt
   );

  [DllImport("testDll.dll",CharSet=CharSet.Unicode)]
  public static extern void desKey(
   [MarshalAs(UnmanagedType.LPStr)]
   ref String  key,
   
   //值类型
   short edf);

  [DllImport("testDll.dll",CharSet=CharSet.Unicode)]
  public static extern void useKey(
   ref long from);

  //值类型指针
  [DllImport("testDll.dll",CharSet=CharSet.Unicode)]
  public static extern void cpKey(ref long into);

  [DllImport("testDll.dll",CharSet=CharSet.Unicode)]
  public static extern void desCrypt(
   [MarshalAs(UnmanagedType.LPStr)]
   ref String inblock,
   [MarshalAs(UnmanagedType.LPStr)]
   ref String outblock);
 }





调用函数

//返回值长度
String sOutput = new String('\n', 10);
   String sKey = "abcd";
   short nKey=0;
   CryptMath.desKey(ref sKey, nKey);
   CryptMath.desCrypt(ref szSrc, ref sOutput);
   MessageBox.Show(sOutput);
   CryptMath.desKey(ref sKey, 1);
   CryptMath.desCrypt(ref sOutput, ref szSrc);
   MessageBox.Show(szSrc);