向数据库中上传图片

protected void Button2_Click(object sender, EventArgs e)
    {
        string lastName = FileUpload1.FileName.Substring(FileUpload1.FileName.LastIndexOf(".") + 1);

        if (lastName.ToLower() == "jpg" || lastName.ToLower() == "bmp" || lastName.ToLower() == "gif")
        {
            int len = FileUpload1.PostedFile.ContentLength;
            Byte[] pictureData = new byte[len];  //将图片转换成二进制
            HttpPostedFile htp = FileUpload1.PostedFile;
            Stream srm = htp.InputStream;
            srm.Read(pictureData, 0, len);
            SqlConnection conn = new SqlConnection("Data Source=tiger;Initial Catalog=liuyan;Integrated Security=True");
            conn.Open();
            string sqlsel = "select * from tb_pic";
            SqlDataAdapter ada = new SqlDataAdapter(sqlsel, conn);
            DataSet ds = new DataSet();
            ada.Fill(ds);
            DataList1.DataSource = ds;
            DataList1.DataBind();
            SqlCommand comd = new SqlCommand("insert into tb_pic (username,name,pic) values ('" + TextBox4.Text + "','" + FileUpload1.FileName + "',@pictureData)", conn);
            comd.Parameters.Add("@pictureData", SqlDbType.Image);
            comd.Parameters["@pictureData"].Value = pictureData;
            comd.ExecuteNonQuery();
            DataList1.DataBind();
            conn.Close();

            Response.Write(" <script>alert('添加成功！')location='tupian.aspx' </script>");
      }
    }