Asp.net把图片存入数据库和使用文件流来读取显示

1、将图片装换为二进制数值(byte[])

byte [] fileData=this.FileUpload1.FileBytes;

2、根据路径将文件装换为二进制数组

  private byte[] returnbyte(string strpath)
        {
            //以二进制方式读文件
            FileStream fsMyfile = new FileStream(strpath, FileMode.OpenOrCreate, FileAccess.ReadWrite);
            //创建一个二进制数据流读入器，和打开的文件关联
            BinaryReader brMyfile = new BinaryReader(fsMyfile);
            //把文件指针重新定位到文件的开始
            brMyfile.BaseStream.Seek(0, SeekOrigin.Begin);
            byte[] bytes = brMyfile.ReadBytes(Convert.ToInt32(fsMyfile.Length.ToString()));
            //关闭以上的new的各个对象
            brMyfile.Close();
            return bytes;
        }

3、Image类型得到二进制数组

 public static byte[] Getbyte(Image img)
        {
            MemoryStream stream = new MemoryStream();
            img.Save(stream, ImageFormat.Jpeg); //Image.FromFile(Path).Save(stream, ImageFormat.Jpeg); ;
            byte[] mydata = new byte[stream.Length];
            mydata = stream.ToArray();
            stream.Close();
            return mydata;
        }

二、图片的显示

读取image类型的数据并显示在网页上的方式如下

1、直接返回image类型

private System.Drawing.Image GetImageDataFromDB()
        {
            string sql = "select Picture from TPicture where ID=1";
            string strconn = System.Configuration.ConfigurationManager.ConnectionStrings["Conn"].ToString();
            SqlConnection conn = new SqlConnection(strconn);
            SqlCommand cmd = new SqlCommand(sql, conn);
            conn.Open();
            byte[] filedata = (byte[])cmd.ExecuteScalar();
            conn.Close();
            System.IO.MemoryStream ms = new MemoryStream(filedata);
            System.Drawing.Image img = System.Drawing.Image.FromStream(ms);
            return img;

        }

2、利用页面输出来显示图片

页面ShowImage.aspx(Page_Load)方法

 protected void Page_Load(object sender, EventArgs e)
        {
            string sql = "select Picture from TPicture";
            string strconn = System.Configuration.ConfigurationManager.ConnectionStrings["Conn"].ToString();
            SqlConnection conn = new SqlConnection(strconn);
            SqlDataAdapter da = new SqlDataAdapter(sql, conn);
            DataTable dt = new DataTable();
            da.Fill(dt);
            byte[] logoimg = (byte[])dt.Rows[0]["Picture"];
            if (logoimg.Length > 0)
            {
                System.Drawing.Image img;
                MemoryStream ms = new MemoryStream(logoimg);
                Response.Clear();
                Response.ContentType = "image/gif";
                Response.OutputStream.Write(logoimg, 0, logoimg.Length);
                Response.End();
            }
        }

图片路径写为：

图片在数据库中的类型设置为image类型

示例：

 SqlConnection conn = new SqlConnection(strconn);

                conn.Open();
                string sql = "insert into TPicture(Picture) values(@Picture)";
                SqlCommand cmd = new SqlCommand(sql, conn);
                SqlParameter para = new SqlParameter("@Picture", SqlDbType.Image);
                //para.Value = FileUpload1.FileBytes;
                para.Value = Getbyte(null);//字节数组
                cmd.Parameters.Add(para);
                cmd.ExecuteNonQuery();