Question

以下代码有什么问题。给定的代码不是CA2000的投诉：在丢失范围之前处置对象（https://msdn.microsoft.com/library/ms182289.aspx）..此代码生成以下警告

警告CA2000在方法'CryptoComputer.Encrypt（string，string，string，string）'中，对象'new RijndaelManaged（）'未沿所有异常路径放置。在对所有引用超出范围之前，调用System.IDisposable.Dispose对象'new RijndaelManaged（）'。

 public static string Encrypt(string plainText, string passPhrase, string saltValue, string initVector)
            {
                var initVectorBytes = Encoding.UTF8.GetBytes(initVector);
                var saltValueBytes = Encoding.UTF8.GetBytes(saltValue);
                var plainTextBytes = Encoding.UTF8.GetBytes(plainText);
                string cipherText;
                PasswordDeriveBytes password = null;
                RijndaelManaged symmetricKey = null;
                MemoryStream memoryStream = null;
                try
                {
                    memoryStream = new MemoryStream();

                    password = new PasswordDeriveBytes(passPhrase, saltValueBytes, hashAlgorithm, passwordIterations);
                    byte[] keyBytes = password.GetBytes(keySize / 8);

                    symmetricKey = new RijndaelManaged { Mode = CipherMode.CBC };
                    var encryptor = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes);

                    var cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write);

                    cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);

                    cryptoStream.FlushFinalBlock();

                    var cipherTextBytes = memoryStream.ToArray();


                    cipherText = Convert.ToBase64String(cipherTextBytes);

                }
                catch (Exception)
                {

                    throw;
                }
                finally
                {
                    password?.Dispose();
                    symmetricKey?.Dispose();
                    memoryStream?.Dispose();

                }

                return cipherText;
            }

如何重写此代码以满足Microsoft指南

Answer 1

使用（...）＆＃34;

中的每个一次性物品

cmd + c

using Statement (C# Reference)

Answer 2

使用如下所示的Using { ... }块包裹它，这将确保一次性实例一旦超出范围就被处理掉。确保将所有一次性物品包裹在using {}块中，而不仅仅是下面显示的那个。

using (symmetricKey = new RijndaelManaged { Mode = CipherMode.CBC })
{
  //rest code goes here
}

.NET代码分析警告

2 个答案: