关于图片上传数据库，下载到picturebox里的操作。

 

1.首先创建数据

id yqid zlbh zlmc zltp（资料图片img格式）
lab_yqgl_da

我的数据库及字段。

2.在窗体的代码模块顶部插入 using 语句：（操作图片后面添加，请查看！）

3.添加 Button按钮，上传图片，还要加一个openFileDialog1，代码如下

private void bt_upload_Click(object sender, EventArgs e)
        {
            this.openFileDialog1.ShowDialog();
        }
        //读取图片
        private string filename;
        private void openFileDialog1_FileOk(object sender, CancelEventArgs e)
        {
            if (pictureBox1.Image != null)
            {
                this.pictureBox1.Image = null;
            }
            //上传图片到pictureBox1
            FileStream fs = new FileStream(openFileDialog1.FileName, FileMode.Open, FileAccess.Read);
            Bitmap bmp = new Bitmap(fs);
            this.pictureBox1.Image = bmp;
            //图像适合图片框的大小
            this.pictureBox1.SizeMode = System.Windows.Forms.PictureBoxSizeMode.StretchImage;
            fs.Close();
            filename = openFileDialog1.FileName.ToString();
        }

4.向数据库里添加图片。

在Button添加按钮里

//id自动生成
            string sqlid = "select max(id) from lab_yqgl_da";
            SqlCommand cmd = new SqlCommand(sqlid, alluse.Class1.conn1);
            string id1 = Convert.ToString(cmd.ExecuteScalar());
            if (id1 == "")
            {
                id = "1";
            }
            else
            {
                int da = Int32.Parse(id1) + 1;
                id = da.ToString();
            }
            //
            string zlbh = this.comboBox1.Text.Trim().ToString();
            string zlmc = this.comboBox2.Text.Trim().ToString();

            string strsql = "insert into lab_yqgl_da(id,yqid,zlbh,zlmc,zltp) values('" + id + "','" +
                yqgl_da_add_yqid + "','" + zlbh + "','" + zlmc + "',@img)";
            SqlCommand mycmd = new SqlCommand(strsql, alluse.Class1.conn1);
            //加入图片
            SqlParameter prm = new SqlParameter("@img", SqlDbType.Image);
            MemoryStream ms = new MemoryStream();
            System.Drawing.Image img = System.Drawing.Image.FromFile(filename);
            img.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
            prm.Value = ms.GetBuffer();
            mycmd.Parameters.Add(prm);
            //
            int n = mycmd.ExecuteNonQuery();
            if (n > 0)
            {
                Class1.tt = new string[] { id, yqgl_da_add_yqid, zlbh, zlmc };
                Class1.hasdo = "yes";
                this.Close();
            }
            else
            {
                MessageBox.Show("添加失败！" + e.ToString());
            }

5.读取图片

 string sql = "select yqid,zlbh,zlmc,zltp from lab_yqgl_da where id='" + yqgl_da_change_id + "'";
            SqlCommand cmd = new SqlCommand(sql, alluse.Class1.conn1);
            SqlDataAdapter sda = new SqlDataAdapter(cmd);
            DataSet ds = new DataSet();
            sda.Fill(ds, "lab_yqgl_da");
            int m = ds.Tables["lab_yqgl_da"].Rows.Count;
            if (m > 0)
            {
                yqid = ds.Tables["lab_yqgl_da"].Rows[0]["yqid"].ToString();
                this.comboBox1.Text = ds.Tables["lab_yqgl_da"].Rows[0]["zlbh"].ToString();
                this.comboBox2.Text = ds.Tables["lab_yqgl_da"].Rows[0]["zlmc"].ToString();
                //图片传到picturebox上。
                Byte[] bytes = new Byte[0];
                bytes = (Byte[])(ds.Tables["lab_yqgl_da"].Rows[m - 1]["zltp"]);
                MemoryStream ms = new MemoryStream(bytes);
                this.pictureBox1.Image = Image.FromStream(ms);
                this.pictureBox1.SizeMode = System.Windows.Forms.PictureBoxSizeMode.StretchImage;
                //
            }

 

缺陷

• 此测试不适用于 Access 和 SQL Server 中的罗斯文示例数据库的雇员表中的照片列。存储在照片列中的位图图像用由 Visual Basic 6.0 OLE Container 控件创建的标题信息进行了包装。
• 如果需要使用 Access 数据库测试此代码，则需要在 Access 表中创建一个 OLE Object 类型的列，并使用 Microsoft Jet 4.0 Provider 中的 System.Data.OleDb 名称空间代替 System.Data.SqlClient 名称空间。