MD5文件去重

     //计算文件的MD5码

        private string getMD5Hash(string pathName)

        {

            string strResult = "";

            string strHashData = "";

            byte[] arrbytHashValue;

            System.IO.FileStream oFileStream = null;

            System.Security.Cryptography.MD5CryptoServiceProvideroMD5Hasher =

                       newSystem.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);//计算指定Stream 对象的哈希值

                oFileStream.Close();

                //由以连字符分隔的十六进制对构成的String，其中每一对表示value 中对应的元素；例如“F-2C-4A”

                strHashData = System.BitConverter.ToString(arrbytHashValue);

                //替换-

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

                strResult = strHashData;

            }

            catch (System.Exception ex)

            {

                MessageBox.Show(ex.Message);

            }

            return strResult;

        }