C#读写图片文件到Access数据库中

今天学习了把图片文件读写到数据库中，我是用的Access数据库，SQL还没去测试，不过都差不多

数据库表的样式

练习嘛就随便弄了下，说明下图片转成的字符串要用备注类型才可以哦

如果用的Sql数据库的话就用最大的字符类型吧

1。写入图片文件到数据库中

 //Access数据库连接字符串
        const string conStr = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=D:\MyAccessFile\MyPicte.accdb;Persist Security Info=False";

        string pic = string.Empty; //保存图片转化字符串

        //选择图片并写入数据库中
        private void button1_Click(object sender, EventArgs e)
        {
            //打开文件对话框选择图片文件
            OpenFileDialog openfile = new OpenFileDialog();
            openfile.Title = "请选择图片";
            openfile.Filter="图片(*.jpg;*.bmp;*.png)|*.jpeg;*.jpg;*.bmp;*.png|AllFiles(*.*)|*.*";
            if (DialogResult.OK != openfile.ShowDialog())
                return;

            try
            {
                //显示图片到PictureBox控件中
                Bitmap bmp = new Bitmap(openfile.FileName);
                pictureBox1.Image = bmp;
                pictureBox1.SizeMode = PictureBoxSizeMode.Zoom;

                //把图片转化成二进制，最后转成字符串
                MemoryStream ms = new MemoryStream();
                bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
                byte[] arr = new byte[ms.Length];
                ms.Position = 0;
                ms.Read(arr, 0, (int)ms.Length);
                ms.Close();
                pic = Convert.ToBase64String(arr);  //把Byte字节数组转成字符串

                //pic = ImageToString(openfile.FileName);//自己写的图片转字符串的函数封装

                //写入数据库中
                OleDbConnection conn = new OleDbConnection(conStr);
                string sql = $"insert into mTable (pictName,pictText) values ('{openfile.FileName}','{pic}')";
                OleDbCommand cmd = new OleDbCommand(sql, conn);
                conn.Open();
                int res = cmd.ExecuteNonQuery();
                if (res > 0)
                {
                    MessageBox.Show("图片保存成功！");
                }
                conn.Close();
                conn.Dispose();
            }
            catch (Exception)
            {

                throw;
            }
        }

2。从数据库中读取图片文件

//从数据库中读取图片，并显示在PictureBoc控件中
        private void button2_Click(object sender, EventArgs e)
        {
            int id = 6;//要读取的图片在数据库中的编号，因为是测试就手动修改要读取的编号
            try
            {
                OleDbConnection conn = new OleDbConnection(conStr);
                string sql = $"select pictText from mTable where ID={id}";
                OleDbCommand cmd = new OleDbCommand(sql, conn);
                conn.Open();
                OleDbDataAdapter oda = new OleDbDataAdapter(cmd);
                DataTable dt = new DataTable();
                oda.Fill(dt);
                conn.Close();
                conn.Dispose();

                if(dt.Rows.Count>0)
                {
                    pic = dt.Rows[0][0].ToString();
                    if (!string.IsNullOrEmpty(pic))
                    {
                        //把string转成字节数组
                        byte[] imageBytes = Convert.FromBase64String(pic);
                        //把字节读取到内存
                        MemoryStream memoryStream = new MemoryStream(imageBytes, 0, imageBytes.Length);
                        memoryStream.Write(imageBytes, 0, imageBytes.Length);

                        //字节数组转成Image对象
                        Image image = Image.FromStream(memoryStream);

                        //Image image = StringToImage(pic);

                        //显示图片到控件中
                        this.pictureBox2.SizeMode = PictureBoxSizeMode.Zoom;
                        this.pictureBox2.Image = image;
                    }
                }
            }
            catch (Exception)
            {

                throw;
            }
        }

学习成果展示：

好了今天就学到这了。