C#数据库保存图片

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.OleDb;
using System.IO;

namespace SendEMail
{
    public partial class frmSaveImg : Form
    {

        OleDbConnection conn;
        public frmSaveImg()
        {
            InitializeComponent();
            //OleDbConnection连接字符串
            string strConn = @"provider=Microsoft.Jet.OLEDB.4.0;data source=" + Application.StartupPath + "\\db1.mdb";
            //创建OleDbConnection对象
            conn = new OleDbConnection(strConn);
        }

        /// <summary>
        /// 执行SQL语句函数
        /// </summary>
        /// <param name="sqlcmd">SQL语句</param>
        /// <param name="paras">SQL语句中的参数组</param>
        /// <returns>返回受影响记录条数</returns>
        public int ExecuteSql(string sqlcmd,params OleDbParameter[] paras)
        {
            OleDbCommand cmd = new OleDbCommand(sqlcmd, conn);
            if (conn.State == ConnectionState.Closed)
            {
                conn.Open();
            }

            foreach (OleDbParameter p in paras)
            {
                cmd.Parameters.Add(p);
            }

            int cnt = cmd.ExecuteNonQuery();
            conn.Close();
            return cnt;
        }

        /// <summary>
        /// 执行SQL查询
        /// </summary>
        /// <param name="sqlcmd">SQL语句</param>
        /// <returns>返回数据表</returns>
        public DataTable QuerySql(string sqlcmd)
        {
            OleDbDataAdapter oda = new OleDbDataAdapter(sqlcmd, conn);
            DataTable dt = new DataTable();
            oda.Fill(dt);
            return dt;
        }

        //单击pictureBox1是执行
        private void pictureBox1_Click(object sender, EventArgs e)
        {
            //打开文件对话框
            OpenFileDialog ofd = new OpenFileDialog();
            //选择图片后，点击确定按钮，加载图片
            if (ofd.ShowDialog() == DialogResult.OK)
            {
                pictureBox1.ImageLocation= ofd.FileName;
            }
        }

        //单击保存按钮执行图片保存到数据库中
        private void button1_Click(object sender, EventArgs e)
        {
            //插入数据SQL语句， img字段为表中存储图片的字段（ole类型）
            string sql = "insert into tb_img (img) values (@img)";

            //读取图片文件流
            FileStream fs = File.Open(pictureBox1.ImageLocation, FileMode.Open, FileAccess.Read);
            //将流转化为byte数组
            byte[] MyData = new byte[fs.Length];
            fs.Read(MyData, 0, MyData.Length);
            fs.Close();

            //给SQL语句中的参数@img, 赋值
            OleDbParameter p = new OleDbParameter("@img", MyData);
            //执行SQL语句，将数据插入表中
            ExecuteSql(sql, p);

            //刷新comboBox1
            comboBox1.ValueMember = "id";
            comboBox1.DisplayMember = "id";
            comboBox1.DataSource = QuerySql("select id from tb_img");
        }

        //当comboBox1的index改变时执行
        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            //得到当前comboBox1选中的记录
            DataTable dt = QuerySql("select * from tb_img where id =" + comboBox1.SelectedValue.ToString());
            //将值强转为byte数组
            byte[] MyData = (byte[])dt.Rows[0]["img"];
            //将byte[]数组写入到流中
            MemoryStream s = new MemoryStream();
            s.Write(MyData, 0, MyData.Length);
            //pictureBox1加载得到的流
            pictureBox1.Image = Image.FromStream(s);
        }

        //窗体启动时，comboBox1绑定数据库
        private void frmSaveImg_Load(object sender, EventArgs e)
        {
            comboBox1.ValueMember = "id";
            comboBox1.DisplayMember = "id";
            comboBox1.DataSource = QuerySql("select id from tb_img");
        }
    }
}