在网上看到一段代码，在程序使用过程中 调用，老是提示Base-64 字符数组的无效长度
在网上看到一段代码，在程序使用过程中 调用，老是提示Base-64 字符数组的无效长度

string key1 = textBox2.Text;
  string enstr = textBox1.Text;
  this.textBox3.Text = dl.DESDecrypt(enstr, key1);
请问该怎么调用个

#region DES 加密解密
  /// <summary>
  /// DES 加密(数据加密标准，速度较快，适用于加密大量数据的场合)
  /// </summary>
  /// <param name="EncryptString">待加密的密文</param>
  /// <param name="EncryptKey">加密的密钥</param>
  /// <returns>returns</returns>
  public static string DESEncrypt(string EncryptString, string EncryptKey)
  {
  if (string.IsNullOrEmpty(EncryptString)) { throw (new Exception("密文不得为空")); }
  if (string.IsNullOrEmpty(EncryptKey)) { throw (new Exception("密钥不得为空")); }
  if (EncryptKey.Length != 8) { throw (new Exception("密钥必须为8位")); }
  byte[] m_btIV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
  string m_strEncrypt = "";
  DESCryptoServiceProvider m_DESProvider = new DESCryptoServiceProvider();
  try
  {
  byte[] m_btEncryptString = Encoding.Default.GetBytes(EncryptString);
  MemoryStream m_stream = new MemoryStream();
  CryptoStream m_cstream = new CryptoStream(m_stream, m_DESProvider.CreateEncryptor(Encoding.Default.GetBytes(EncryptKey), m_btIV), CryptoStreamMode.Write);
  m_cstream.Write(m_btEncryptString, 0, m_btEncryptString.Length);
  m_cstream.FlushFinalBlock();
  m_strEncrypt = Convert.ToBase64String(m_stream.ToArray());
  m_stream.Close(); m_stream.Dispose();
  m_cstream.Close(); m_cstream.Dispose();
  }
  catch (IOException ex) { throw ex; }
  catch (CryptographicException ex) { throw ex; }
  catch (ArgumentException ex) { throw ex; }
  catch (Exception ex) { throw ex; }
  finally { m_DESProvider.Clear(); }

  return m_strEncrypt;
  }



------解决方案--------------------
http://topic.csdn.net/u/20071223/14/47c90937-abdf-42c2-b13a-202d70940b84.html
------解决方案--------------------
系统有对 Base64 加密 和解密 方法，

长度 无效 就证明你的 字符串 根本就不是 Base64 字符串。