winform图片读取存储于数据库SQL

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

namespace WindowsFormsApplication10
{
    public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            openFileDialog1.Filter = "@.Jpg|*.jpg|@.Gif|*.gif|@.Png|*.png|All files|*.*";
            DialogResult dr = openFileDialog1.ShowDialog();

            if (dr == DialogResult.OK)
            {
                //将图片读入到文件流
                FileStream fs = new FileStream(openFileDialog1.FileName,FileMode.Open,FileAccess.Read);//路径
                Image img = System.Drawing.Bitmap.FromStream(fs);//绘制，流转成图片
                pictureBox1.Image = img;//指定，显示图片
                fs.Close();

            }
        }

        private void button2_Click(object sender, EventArgs e)//存入数据库
        {
            openFileDialog1.Filter = "@.Jpg|*.jpg|@.Gif|*.gif|@.Png|*.png|All files|*.*";
            DialogResult dr = openFileDialog1.ShowDialog();
            if (dr == DialogResult.OK)
            {
                //文件流
                FileStream fs = new FileStream(openFileDialog1.FileName,FileMode.Open,FileAccess.Read);
                BinaryReader br = new BinaryReader(fs);//二进制读取器
                byte[] buffer =  br.ReadBytes(int.Parse(fs.Length.ToString()));

                //连接数据库
                SqlConnection conn = new SqlConnection("server=.;database=snewData;user=sa;pwd=");
                SqlCommand cmd = conn.CreateCommand();
                cmd.CommandText = "insert into imgtable values(@buffer)";
                cmd.Parameters.Add("@buffer",buffer);
                conn.Open();
                cmd.ExecuteNonQuery();
                cmd.Dispose();
                conn.Close();
            }
        }

        private void button3_Click(object sender, EventArgs e)//数据库读取
        {
            //读取数据库
            byte[] buffer = null;
            SqlConnection conn = new SqlConnection("server=.;database=snewData;user=sa;pwd=");
            SqlCommand cmd = conn.CreateCommand();
            cmd.CommandText = "select *from imgtable where code=4";
            conn.Open();
            SqlDataReader dr = cmd.ExecuteReader();
            if (dr.Read())
            {
                 buffer = (byte[])dr["imgs"];
            }
            cmd.Dispose();
            conn.Close();
            //将二进制数据buffer显示为图片
            MemoryStream ms = new MemoryStream(buffer);//构建对象
            ms.Write(buffer,0,buffer.Length);//写到内存流中
            Image img = System.Drawing.Image.FromStream(ms);
            pictureBox1.Image = img;

        }
    }
}