在SQLServer数据库中读写图片

简单地从数据库写入与读取图片文件，代码如下

       //将图片转化为字节数组写入数据库
        private void button3_Click(object sender, EventArgs e)
        {
            string _filePath = Application.StartupPath + "\\index1.jpg";
            FileStream _stream = new FileStream(_filePath, FileMode.Open,FileAccess.Read);
            byte[] _aryByte = new byte[_stream.Length];
            _stream.Read(_aryByte, 0, _aryByte.Length);
            string _sConnection = "Provider=SQLOLEDB;Data Source=127.0.0.1;Initial Catalog=Northwind;User Id=sa;Password=";
            OleDbConnection _conn = null;
            try
            {
                _conn = new OleDbConnection(_sConnection);
                _conn.Open();
                //通过OLEDB连接，参数为?,如果使用ado连接，参数为@参数名
                string _sql = "insert into TestImage(UserName,Image)values(?,?)";                 OleDbCommand _command = new OleDbCommand(_sql, _conn);
                _command.CommandType = CommandType.Text;
                _command.Parameters.Add("?", OleDbType.VarChar, 255).Value = "lins";
                _command.Parameters.Add("?", OleDbType.Binary).Value = _aryByte;
                _command.ExecuteNonQuery();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
            finally
            {
                _conn.Close();
                _conn = null;
            }
        }

        //从数据库中读取图片
        private void button4_Click(object sender, EventArgs e)
        {
            string _sConnection = "Provider=SQLOLEDB;Data Source=127.0.0.1;Initial Catalog=Northwind;User Id=sa;Password=";
            OleDbConnection _conn = null;
            try
            {
                _conn = new OleDbConnection(_sConnection);
                _conn.Open();
                string _sql = "select Image from TestImage where username = 'lins'";
                OleDbCommand _command = new OleDbCommand(_sql, _conn);
                OleDbDataReader _reader = _command.ExecuteReader();
                while (_reader.Read())
                {
                    byte[] _ary = (byte[])_reader["image"];
                    MemoryStream _stream = new MemoryStream(_ary);
                    Image _img = Image.FromStream(_stream);
                    Graphics _g = this.CreateGraphics();
                    _g.DrawImage(_img, new Point(0, 0));
                }
                _command.ExecuteNonQuery();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
            finally
            {
                _conn.Close();
                _conn = null;
            }
        }