C# MD5校正

標籤：比較   null   catch   com   檔案   builder   omd   大檔案   data   

1.方法1

private static string GetMD5HashFromFile(string fileName) { try { FileStream file = new FileStream(fileName, FileMode.Open); System.Security.Cryptography.MD5 md5 = new System.Security.Cryptography.MD5CryptoServiceProvider(); byte[] retVal = md5.ComputeHash(file); file.Close(); StringBuilder sb = new StringBuilder(); for (int i = 0; i < retVal.Length; i++) { sb.Append(retVal[i].ToString(“x2″)); } return sb.ToString(); } catch (Exception ex) { throw new Exception(“GetMD5HashFromFile() fail,error:” + ex.Message); } }
2.方法2

    //計算檔案的MD5碼

        private string getMD5Hash(string pathName)

        {

            string strResult = "";

            string strHashData = "";

            byte[] arrbytHashValue;

            System.IO.FileStream oFileStream = null;

            System.Security.Cryptography.MD5CryptoServiceProvider oMD5Hasher = new System.Security.Cryptography.MD5CryptoServiceProvider();

　　　　try

            {

                oFileStream = new System.IO.FileStream(pathName, System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.ReadWrite));

                arrbytHashValue = oMD5Hasher.ComputeHash(oFileStream);//計算指定Stream 對象的雜湊值

                oFileStream.Close();

                //由以連字號分隔的十六進位對構成的String，其中每一對錶示value 中對應的元素；例如“F-2C-4A”

                strHashData = System.BitConverter.ToString(arrbytHashValue);

                //替換-

                strHashData = strHashData.Replace("-", "");

                strResult = strHashData;

            }

            catch (System.Exception ex)

            {

                MessageBox.Show(ex.Message);

　　　　　}

            return strResult;

        }

3.比較。

方法1和方法2雖然都能計算檔案的MD5，但是方法2在針對大檔案時，更快，所以更好。

 

C# MD5校正