C# MySqlDataReader.GetBytes方法代码示例

        public static byte[] convertBlobToBufferData(String column,MySqlDataReader rdr)
        {
            int bufferSize = 1024; // Number of bytes to read at a time
            byte[] ImageData = new byte[bufferSize];
            long nBytesReturned, startIndex = 0;
            int ordinal = rdr.GetOrdinal(column);
            string image = rdr.IsDBNull(ordinal) ? null : rdr.GetString(column);
            if (image != null)
            {
                startIndex = 0;

                nBytesReturned = rdr.GetBytes(
                ordinal, // Column index of BLOB column
                startIndex, // Start position of the byte to read
                ImageData, // Byte array to recieve BLOB data
                0, // Start index of the array
                bufferSize // Size of buffer
                );
                while (nBytesReturned == bufferSize)
                {
                    startIndex += bufferSize;
                    nBytesReturned = rdr.GetBytes(ordinal, startIndex, ImageData, 0, bufferSize); // Number of bytes returned is assigned to nBytesReturned
                }
                return ImageData;
            }
            else
            {
                return null;
            }
        }

    /// <summary>
    /// Downloads the save.
    /// </summary>
    /// <param name="lun">Lun. Logged in User</param>
    /// <param name="path">Path. path for saving the zip</param>
    public void DownloadSave()
    {
        if (loggedIn) {

            string lun = LoggedInUser;

            int db_FileSize;
            byte[] rawData;
            FileStream fs;

            //int db_id;
            //string db_name;
            //string db_password;

            openConnection (true);

            try {

                string sql = "SELECT save, filesize FROM savebase.saves WHERE [email protected]";
                cmd = new MySqlCommand (sql, conn);
                cmd.CommandText = sql;
                cmd.Parameters.AddWithValue ("@username", lun);

                myData = cmd.ExecuteReader ();

                if (! myData.HasRows){
                    throw new Exception("There are no rows");
                }

                myData.Read();

                db_FileSize = myData.GetInt32("filesize");
                if (db_FileSize <= 0)
                {

                    // Debug.Log("no remote save found");
                }
                else
                {
                    rawData = new byte[db_FileSize];

                    myData.GetBytes(myData.GetOrdinal("save"), 0, rawData, 0, db_FileSize);

                    fs = new FileStream(@path, FileMode.Create, FileAccess.Write);
                    fs.Write(rawData, 0, db_FileSize);
                    fs.Close();
                    myData.Close();
                    conn.Close();
                    Decompress();

                    if (SceneManager.GetActiveScene().buildIndex == 0)
                    {
                        feedback.enabled = true;
                        feedbackText.text = "Savegame succesfully downloaded, press Load Game game now";
                    }
                }

            } catch (Exception ex) {
                Debug.Log (ex.Message.ToString ());
                if (ex is MySqlException) {
                    MySqlException ex2 = (MySqlException)ex;
                    Debug.Log (ex2.Number);
                }
                Debug.Log (ex.ToString ());

                throw ex;
            } finally {
                conn.Close ();
            }
        }
    }

 // 取 dr 中某字段的数据并返回
 public static object GetValue( DbColumn col, MySqlDataReader r, int idx )
 {
     switch( col.dataType )
     {
     case DbDataTypes.Boolean:
         return r.GetBoolean( idx );
     case DbDataTypes.Int8:
         return r.GetSByte( idx );
     case DbDataTypes.Int16:
         return r.GetInt16( idx );
     case DbDataTypes.Int32:
         return r.GetInt32( idx );
     case DbDataTypes.Int64:
         return r.GetInt64( idx );
     case DbDataTypes.UInt8:
         return r.GetByte( idx );
     case DbDataTypes.UInt16:
         return r.GetUInt16( idx );
     case DbDataTypes.UInt32:
         return r.GetUInt32( idx );
     case DbDataTypes.UInt64:
         return r.GetUInt64( idx );
     case DbDataTypes.Float:
         return r.GetFloat( idx );
     case DbDataTypes.Double:
         return r.GetDouble( idx );
     case DbDataTypes.DateTime:
         return r.GetDateTime( idx );
     case DbDataTypes.String:
         return r.GetString( idx );
     case DbDataTypes.Bytes:
         var len = (int)r.GetBytes( idx, 0, null, 0, 0 );
         var buf = new byte[ len ];
         r.GetBytes( idx, 0, buf, 0, len );
         return buf;
     default:
         throw new Exception( "unsupported DbType" );
     }
 }

 // 往 dr 填充 r 于 i 索引的值
 public static void FillValue( DbRow dr, MySqlDataReader r, int i )
 {
     switch( dr.parent.columns[ i ].dataType )
     {
     case DbDataTypes.Boolean:
         dr[ i ].Assign( r.GetBoolean( i ) ); break;
     case DbDataTypes.Int8:
         dr[ i ].Assign( r.GetSByte( i ) ); break;
     case DbDataTypes.Int16:
         dr[ i ].Assign( r.GetInt16( i ) ); break;
     case DbDataTypes.Int32:
         dr[ i ].Assign( r.GetInt32( i ) ); break;
     case DbDataTypes.Int64:
         dr[ i ].Assign( r.GetInt64( i ) ); break;
     case DbDataTypes.UInt8:
         dr[ i ].Assign( r.GetByte( i ) ); break;
     case DbDataTypes.UInt16:
         dr[ i ].Assign( r.GetUInt16( i ) ); break;
     case DbDataTypes.UInt32:
         dr[ i ].Assign( r.GetUInt32( i ) ); break;
     case DbDataTypes.UInt64:
         dr[ i ].Assign( r.GetUInt64( i ) ); break;
     case DbDataTypes.Float:
         dr[ i ].Assign( r.GetFloat( i ) ); break;
     case DbDataTypes.Double:
         dr[ i ].Assign( r.GetDouble( i ) ); break;
     case DbDataTypes.DateTime:
         dr[ i ].Assign( r.GetDateTime( i ) ); break;
     case DbDataTypes.String:
         dr[ i ].Assign( r.GetString( i ) ); break;
     case DbDataTypes.Bytes:
         var len = (int)r.GetBytes( i, 0, null, 0, 0 );
         var buf = new byte[ len ];
         r.GetBytes( i, 0, buf, 0, len );
         dr[ i ].Assign( buf );
         break;
     default:
         break;
     }
 }

        public BitmapImage ReadBlobData(int id)
        {
            cmd.CommandText = "select Picture from Products where ID=" + id;
            // Size of the BLOB buffer.
            int bufferSize = 1024;
            // The BLOB byte[] buffer to be filled by GetBytes.
            byte[] outByte = new byte[bufferSize];
            byte[] overallOutByte = null;
            // The bytes returned from GetBytes.
            long retval;
            // The starting position in the BLOB output.
            long startIndex = 0;

            // The publisher id to use in the file name.
            // Open the connection and read data into the DataReader.
            dataReader = cmd.ExecuteReader(CommandBehavior.SequentialAccess);

            while (dataReader.Read())
            {
                // Reset the starting byte for the new BLOB.
                startIndex = 0;
                // Read bytes into outByte[] and retain the number of bytes returned.
                retval = dataReader.GetBytes(0, startIndex, outByte, 0, bufferSize);

                overallOutByte = new byte[bufferSize];
                outByte.CopyTo(overallOutByte, 0);

                // Continue while there are bytes beyond the size of the buffer.
                while (retval == bufferSize)
                {
                    startIndex += bufferSize;
                    retval = dataReader.GetBytes(0, startIndex, outByte, 0, bufferSize);
                    byte[] tmpArr = new byte[overallOutByte.Length];
                    overallOutByte.CopyTo(tmpArr, 0);
                    overallOutByte = new byte[bufferSize + tmpArr.Length];
                    tmpArr.CopyTo(overallOutByte, 0);
                    outByte.CopyTo(overallOutByte, tmpArr.Length);
                }
            }
            dataReader.Close();
            return ConvertByteToImg(overallOutByte);
        }