C#在SQl中存取图片image

（1）控制台应用程序下演示插入图片

    public void InsertIMG()
    {

        //将需要存储的图片读取为数据流
        FileStream fs = new FileStream(@"E:\c.jpg", FileMode.Open,FileAccess.Read);
        Byte[] btye2 = new byte[fs.Length];
        fs.Read(btye2 , 0, Convert.ToInt32(fs.Length));
        fs.Close();
       
        using (SqlConnection conn = new SqlConnection(sqlconnstr))
        {
            conn.Open();
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = conn;
            cmd.CommandText = "insert into T_Img(imgfile) values(@imgfile)";
            SqlParameter par = new SqlParameter("@imgfile", SqlDbType.Image);
            par.Value = bt;
            cmd.Parameters.Add(par);

            int t=(int)(cmd.ExecuteNonQuery());
            if (t > 0)
            {
                Console.WriteLine("插入成功");
            }
            conn.Close();
        }
    }

（2）控制台应用程序下读出并生成图片到物理位置

    public void Read()
    {
        byte[] MyData = new byte[0];
        using (SqlConnection conn = new SqlConnection(sqlconnstr))
        {
            conn.Open();
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = conn;
            cmd.CommandText = "select * from T_img";
            SqlDataReader sdr = cmd.ExecuteReader();
            sdr.Read();
            MyData = (byte[])sdr["ImgFile"];//读取第一个图片的位流
            int ArraySize= MyData.GetUpperBound(0);//获得数据库中存储的位流数组的维度上限，用作读取流的上限

            FileStream fs = new FileStream(@"c:\00.jpg", FileMode.OpenOrCreate, FileAccess.Write);
            fs.Write(MyData, 0, ArraySize);
            fs.Close();   //-- 写入到c:\00.jpg。
            conn.Close();
            Console.WriteLine("读取成功");//查看硬盘上的文件
        }
    }

（3）Web下picshow.aspx页将图片读取出来并写入到浏览器上呈现

    public void Read()
    {
        byte[] MyData = new byte[0];
        using (SqlConnection conn = new SqlConnection(sqlconnstr))
        {
            conn.Open();
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = conn;
            cmd.CommandText = "select * from T_img";
            SqlDataReader sdr = cmd.ExecuteReader();
            sdr.Read();
            MyData = (byte[])sdr["ImgFile"];
            Response.ContentType = "image/gif";
            Response.BinaryWrite(MyData);
            conn.Close();
            Response.Write("读取成功");
        }
    }

（4）在web中可以如上picshow.aspx页面读取并显示图片，而真正引用该图片时如下示例

<img src="picshow.aspx" width="500" height="300" />
 （5）Winform下将图片写入到sql数据库image类型字段中的方法和以上方法基本一致，仅区别于可以利用多个对话框来帮助选取存储图片等，各个属性可以方便的利用上

（6）Winform下读取图片在picturebox控件中显示出来

方法一：利用MemoryStream 和System.Drawing.Image

    public void Read()
    {
        byte[] MyData = new byte[0];
        using (SqlConnection conn = new SqlConnection(sqlconnstr))
        {
            conn.Open();
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = conn;
            cmd.CommandText = "select * from T_img";
            SqlDataReader sdr = cmd.ExecuteReader();
            sdr.Read();
            MyData = (byte[])sdr["ImgFile"];

            MemoryStream mystream = new MemoryStream(MyData);
            //用指定的数据流来创建一个image图片
            System.Drawing.Image img = System.Drawing.Image.FromStream(mystream, true);
           
            System.Windows.Forms.PictureBox picbox = new PictureBox();
            picbox.Image = img;
            picbox.Left = 30;
            picbox.Top = 80;
            picbox.Width = 800;
            picbox.Height = 500;
            this.Controls.Add(picbox);

            mystream.Close();
            conn.Close();
        }
    }

方法二：将流直接读取成图片并写入到物理位置，然后再行利用该图片呈现

    void Read()
    {
        using (SqlConnection conn = new SqlConnection(sqlconnstr))
        {
            conn.Open();
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = conn;
            cmd.CommandText = "select * from T_img";
            SqlDataReader sdr = cmd.ExecuteReader();
            sdr.Read();

            byte[] Image_img = (byte[])sdr["ImgFile"];
            if (Image_img.Length == 0)
            {
                return;
            }
            int filelength = Image_img.Length;
            string imageName = "1.jpg";
            string myUrl = Environment.CurrentDirectory + "\\" + imageName;
            FileStream fs = new FileStream(myUrl, FileMode.OpenOrCreate,FileAccess.Write);
            BinaryWriter BW = new BinaryWriter(fs);
            BW.BaseStream.Write(Image_img, 0, filelength);
            BW.Flush();
            BW.Close();
            System.Windows.Forms.PictureBox picbox = new PictureBox();
           
            //为picbox添加图片方法一
            //picbox.ImageLocation = myUrl;
            //picbox.Width = 800;
            //picbox.Height = 300;

            //为picbox添加图片方法二
            Bitmap bitmap = new Bitmap(myUrl);
            picbox.Width = 100;//bitmap.Width;
            picbox.Height = 80;//bitmap.Height;
            picbox.Image = (Image)bitmap;
            picbox.SizeMode = System.Windows.Forms.PictureBoxSizeMode.StretchImage;
            picbox.Left = 20;
            picbox.Top = 30;

            this.Controls.Add(picbox);
            conn.Close();
           
        }
    }