C# 访问Access存取图片

图片存入ole字段，看有的代码是获取图片的字节数组转换为base64字符串，存入数据库；显示图片是把base64字符串转换为字节数组再显示；直接存字节数组可能还好一点；

插入的时候用带参数的sql写法比较好；用拼接sql一般会出错；

测试表有三个字段，加载一个图片然后插入记录；

插入以后如下；第5、6条是对的，3、4没插对；如果要png、jpeg、gif等格式都支持，写为 image1.Save(ms, image1.RawFormat)；

读取并显示如下；

插入记录的代码，

            Image image1;MemoryStream ms = new MemoryStream();byte[] arr1 = null; ;if (pictureBox1.Image != null){image1.Save(ms, image1.RawFormat);arr1 = new byte[ms.Length];ms.Position = 0;ms.Read(arr1, 0, (int)ms.Length);//pic1 = Convert.ToBase64String(arr1);}ms.Close();if (button1.Text == "添加"){if (textBox1.Text == ""){MessageBox.Show("名字不能为空！", "添加信息");return;}else{string connectionString = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source='" + Environment.CurrentDirectory + "\\mytest.mdb'";string query = "INSERT INTO testpic (a1, a2, ppp) VALUES (?,?,?)";using (OleDbConnection conn = new OleDbConnection(connectionString)){using (OleDbCommand cmd = new OleDbCommand(query, conn)){// 这里设置参数值，注意索引对应你SQL语句中参数的位置cmd.Parameters.AddWithValue("?", textBox1.Text);cmd.Parameters.AddWithValue("?", textBox2.Text);cmd.Parameters.AddWithValue("?", arr1);conn.Open();int rowsAffected = cmd.ExecuteNonQuery();conn.Close();}}textBox1.Text = "";textBox2.Text = "";}}

读取显示图片的代码，

	private void button2_Click(object sender, EventArgs e){string sql1 = "select * from testpic where id = " + 6;byte[] buff = null;buff = achelp.GetBufferFromDB(sql1, "ppp");System.IO.MemoryStream picbuf = new System.IO.MemoryStream(buff);Image image = Image.FromStream(picbuf, true);picbuf.Close();pictureBox1.Image = image;}......//返回图片byte[]public byte[] GetBufferFromDB(string strSql, string fieldname){byte[] buff = null;if (conn_str == null){return null;}try{ole_connection.Open();//打开连接if (ole_connection.State == ConnectionState.Closed){return null;}ole_command.CommandText = strSql;ole_command.Connection = ole_connection;ole_reader = ole_command.ExecuteReader(CommandBehavior.Default);if (ole_reader.Read()){buff = (byte[])ole_reader[fieldname];}ole_reader.Close();ole_reader.Dispose();}catch (System.Exception e){//Console.WriteLine(e.ToString());MessageBox.Show(e.Message);}finally{if (ole_connection.State != ConnectionState.Closed){ole_connection.Close();}}return buff;}

要先执行ole_reader.Read()，然后才能取ole_reader[fieldname]；