[英]Why Dispose is being called on DataContract even though the service still refers to it?
[英]Still A “Multiple Dispose” Issue, Even Though Handled
在我的一些項目中,我一直在使用一對可靠的數據加密/解密方法(加密方法粘貼在下面)。 但是我一直對CA2202這個關於memoryStream對象的警告(“不要多次放置對象”)感到困惑。 我相信我會以適當的方式處理此問題,但是只要在Visual Studio中運行分析,我仍然會收到警告。 它從未在生產代碼中引發異常,但我仍然想一勞永逸地擺脫警告。 那可能嗎? 還是我應該忽略它? 提前致謝。
public static string Encrypt(string clearText, string passPhrase, string saltValue)
{
byte[] clearTextBytes = Encoding.UTF8.GetBytes(clearText);
byte[] saltValueBytes = Encoding.UTF8.GetBytes(saltValue);
Rfc2898DeriveBytes passPhraseDerviedBytes = new Rfc2898DeriveBytes(passPhrase, saltValueBytes);
byte[] keyBytes = passPhraseDerviedBytes.GetBytes(32);
byte[] initVectorBytes = passPhraseDerviedBytes.GetBytes(16);
RijndaelManaged symmetricKey = new RijndaelManaged() { Mode = CipherMode.CBC };
ICryptoTransform encryptor = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes);
byte[] cipherTextBytes = null;
MemoryStream memoryStream = null;
try
{
memoryStream = new MemoryStream();
using (CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
{
cryptoStream.Write(clearTextBytes, 0, clearTextBytes.Length);
cryptoStream.FlushFinalBlock();
cipherTextBytes = memoryStream.ToArray();
}
}
finally
{
if (memoryStream != null)
{
memoryStream.Dispose();
}
}
return Convert.ToBase64String(cipherTextBytes);
}
這是因為CryptoStream
關閉了memoryStream
您正在使用構造函數
public CryptoStream(Stream stream, ICryptoTransform transform, CryptoStreamMode mode)
: this(stream, transform, mode, false) {
}
哪個電話
public CryptoStream(Stream stream, ICryptoTransform transform, CryptoStreamMode mode, bool leaveOpen) {
_stream = stream;
_leaveOpen = leaveOpen;
//...
}
_leaveOpen
和_stream
稍后在Dispose
protected override void Dispose(bool disposing) {
try {
if (!_leaveOpen) {
_stream.Close();
}
//...
}
}
您可以刪除memoryStream.Dispose();
,或將true
作為參數傳遞給CryptoStream
構造函數
using (CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write, true)) { }
問題在於對CryptoStream.Dispose
的調用可以在給定的流上調用dispose:
protected override void Dispose(bool disposing) { try { if (disposing) { if (!_finalBlockTransformed) { FlushFinalBlock(); } if (!_leaveOpen) { _stream.Close(); } } } ... }
如果您使用帶有4個參數的構造函數:
CryptoStream(Stream stream, ICryptoTransform transform, CryptoStreamMode mode, bool leaveOpen)
最后一個參數確定流是否已關閉。 默認情況下,依次調用Close()
也會調用Dispose
:
public virtual void Close() { /* These are correct, but we'd have to fix PipeStream & NetworkStream very carefully. Contract.Ensures(CanRead == false); Contract.Ensures(CanWrite == false); Contract.Ensures(CanSeek == false); */ Dispose(true); GC.SuppressFinalize(this); }
因此,該檢查似乎無法正確確定特定的Stream實現是否將被Dispose,而退回去認為它將是-這種情況。
但是請注意,在大多數情況下,對MemoryStream
兩次,一次或零次處理並不重要。
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.