Using System.Text;
byte[ ] 转换为string
byte[ ] image;
string ll = Encoding.Default.GetString(image);
string 转换为byte[ ]
string ss;
byte[] b = Encoding.Default.GetBytes(ss);
数据库中image类型的字段的处理。
首先我想从数据库中读出图片(以image类型存储的), 并且写入txt文件中:
private void GetImage() { string conn = "Server=192.168.0.11; User id=user; Pwd=pwd; Database=database"; SqlConnection sqlCon = new SqlConnection(conn); string sql = "SELECT ImageFile, PersonID FROM Persons where PersonID = 1"; SqlCommand myCommand = new SqlCommand(); myCommand.Connection = sqlCon; myCommand.CommandType = CommandType.Text; myCommand.CommandText = sql; DataTable myTable = new DataTable(); SqlDataAdapter myDataAda = new SqlDataAdapter(); myDataAda.SelectCommand = myCommand; try { sqlCon.Open(); myDataAda.Fill(myTable); sqlCon.Close(); if(myTable.Rows.Count>0) { byte[] image = (byte[])myTable.Rows[0]["ImageFile"]; string ll = Encoding.Default.GetString(image); WriteStr(@"F:\test.txt",ll); } } catch(Exception ex) { string err = ex.Message; } finally { sqlCon.Close(); myCommand.Dispose(); myDataAda.Dispose(); } } private void WriteStr(string strLogFileName, string strLogContent) { try { FileInfo objFileInfo = new FileInfo(strLogFileName); using (FileStream objFileStream = objFileInfo.OpenWrite()) { using (StreamWriter objStreamWriter = new StreamWriter(objFileStream)) { objStreamWriter.BaseStream.Seek(0, SeekOrigin.End); objStreamWriter.Write("{0}", strLogContent); } } } catch { } }
其次,需要把图片从txt文件中读出然后存入数据库中。
string ss = ReadStr(@"F:\test.txt"); byte[] b = Encoding.Default.GetBytes(ss); string conn = "Server=server; User id=user; Pwd=pwd; Database=database"; SqlConnection sqlCon = new SqlConnection(conn); string sql = "update Persons set ImageFile=@img where PersonID = 1"; SqlCommand myCommand = new SqlCommand(); SqlParameter sp = new SqlParameter("@img",SqlDbType.Image); myCommand.Connection = sqlCon; myCommand.CommandType = CommandType.Text; myCommand.CommandText = sql; sp.Value = b; myCommand.Parameters.Add(sp); try { sqlCon.Open(); myCommand.ExecuteNonQuery(); sqlCon.Close(); } catch(Exception eS) { string ee = eS.Message; } finally { sqlCon.Close(); myCommand.Dispose(); }