C# 读写ACCESS的OLE对象，演示图片与长文件的读写

网络上的读写OLE对象的代码是多，不过多是转载的，大部分人从来都没实际测试过，只是COPY来COPY去。我重来没看到一个真正可以运行的东东。
没办法，只有自力更生，花了一点时间出了点研究成果，写到这里做个记录。

关键代码如下：

******* void button1_Click(object sender, EventArgs e)  //写入图片
        {
            OpenFileDialog dlg = new OpenFileDialog();
            dlg.Filter = "All   Files|*.*";
            if (dlg.ShowDialog() == DialogResult.OK)
            {
                string fileName = dlg.FileName;

                FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);
                byte[] buffer = new byte[fs.Length];
                fs.Read(buffer, 0, buffer.Length);
                fs.Close();

                //pictureBox1.Image = Image.FromFile(fileName);

                OleDbConnection cn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Application.StartupPath + "\\db1.mdb" + ";Persist Security Info=True");
                cn.Open();

                OleDbCommand cmd = new OleDbCommand("INSERT INTO  list1(pic)  VALUES(@img)", cn);
                ((OleDbParameter)cmd.Parameters.Add("@img", OleDbType.Binary)).Value = buffer;
                cmd.ExecuteNonQuery();
            }  
 

          
    }

        ******* void button2_Click(object sender, EventArgs e)  //读取图片
        {
            OleDbConnection cn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Application.StartupPath + "\\db1.mdb" + ";Persist Security Info=True");
            cn.Open();

            OleDbDataAdapter oda = new OleDbDataAdapter("select  pic  from  list1 where 编号=10", cn);
           

            DataTable dt = new DataTable();
            oda.Fill(dt);

            cn.Close();

            byte[] buffer = dt.Rows[0][0] as byte[];
            MemoryStream ms = new MemoryStream(buffer);

            pictureBox1.Image = Image.FromStream(ms);
        }

        ******* void button3_Click(object sender, EventArgs e)  //写入长文本
        {
            OpenFileDialog dlg = new OpenFileDialog();
            dlg.Filter = "TXT Files|*.txt";
            if (dlg.ShowDialog() == DialogResult.OK)
            {
                string fileName = dlg.FileName;

                FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);
                byte[] buffer = new byte[fs.Length];
                fs.Read(buffer, 0, buffer.Length);
                fs.Close();

                //pictureBox1.Image = Image.FromFile(fileName);

                OleDbConnection cn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Application.StartupPath + "\\db1.mdb" + ";Persist Security Info=True");
                cn.Open();

                OleDbCommand cmd = new OleDbCommand("INSERT INTO  list1(pic)  VALUES(@img)", cn);
                ((OleDbParameter)cmd.Parameters.Add("@img", OleDbType.Binary)).Value = buffer;
                cmd.ExecuteNonQuery();
            }  
        }

        ******* void button4_Click(object sender, EventArgs e)  //载入长文本
        {
            OleDbConnection cn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Application.StartupPath + "\\db1.mdb" + ";Persist Security Info=True");
            cn.Open();

            OleDbDataAdapter oda = new OleDbDataAdapter("select  pic  from  list1 where 编号=12", cn);

            DataTable dt = new DataTable();
            oda.Fill(dt);

            cn.Close();

            byte[] buffer = dt.Rows[0][0] as byte[];
            //MemoryStream ms = new MemoryStream(buffer);
            richTextBox1.Text =System.Text.Encoding.Default.GetString(buffer);

        }