C# - 数据库存取图片

1、创建数据表

CREATE TABLE Tb_pic
(
	ID int primary key identity(1, 1) not null,
	PictureBox varchar(max)
)

运行效果：

2、代码：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

using System.Data.SqlClient;
using System.Configuration;
using System.IO;

namespace Test
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        //定义字节数组，用来存储图片
        byte[] arr;

        //抽取表中的ID字段，绑定combBox数据
        public void GetID()
        {
            this.comboBox1.Items.Clear();
            string constring = ConfigurationManager.ConnectionStrings["ConString"].ConnectionString;
            string sql = "select ID from Tb_pic";
            SqlConnection con = new SqlConnection(constring);
            con.Open();
            SqlCommand cmd = new SqlCommand(sql, con);
            SqlDataReader sdr = cmd.ExecuteReader();
            while (sdr.Read())
            {
                this.comboBox1.Items.Add(sdr["ID"].ToString());
            }
            this.comboBox1.SelectedIndex = 0;
        }

        /// <summary>
        /// 加载事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Form1_Load(object sender, EventArgs e)
        {
            GetID();
        }

        /// <summary>
        /// 浏览事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button1_Click(object sender, EventArgs e)
        {
            OpenFileDialog openfile = new OpenFileDialog();
            openfile.Title = "请选择客户端longin的图片";
            openfile.Filter = "Login图片(*.jpg;*.bmp;*png)|*.jpeg;*.jpg;*.bmp;*.png|AllFiles(*.*)|*.*";
            if (DialogResult.OK == openfile.ShowDialog())
            {
                try
                {
                    Bitmap bmp = new Bitmap(openfile.FileName);
                    pictureBox1.Image = bmp;
                    pictureBox1.SizeMode = PictureBoxSizeMode.Zoom;
                    MemoryStream ms = new MemoryStream();
                    bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
                    arr = new byte[ms.Length];
                    ms.Position = 0;
                    ms.Read(arr, 0, (int)ms.Length);
                    ms.Close();
                }
                catch { }
            }
        }

        /// <summary>
        /// 保存事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button2_Click(object sender, EventArgs e)
        {
            if (arr == null)
            {
                MessageBox.Show("照片为空！","提示");
                return;
            }

            //直接返这个值放到数据就行了

            string sql = "insert into Tb_pic (PictureBox) values (@pic)";

            SqlParameter[] para = new SqlParameter[]
                    {
                        new SqlParameter("@pic", Convert.ToBase64String(arr))
                    };

            string constring = ConfigurationManager.ConnectionStrings["ConString"].ConnectionString;

            SqlConnection con = new SqlConnection(constring);
            con.Open();
            SqlCommand cmd = new SqlCommand(sql, con);
            cmd.Parameters.AddRange(para);
            int i = cmd.ExecuteNonQuery();
            con.Close();

            if (i == 1)
            {
                MessageBox.Show("添加成功！", "提示");
                GetID();
            }
            else
            {
                MessageBox.Show("添加失败!", "提示");
            }
        }

        /// <summary>
        /// 显示事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button3_Click(object sender, EventArgs e)
        {
            if (this.comboBox1.Items.Count <= 0)
            {
                MessageBox.Show("无数据！", "提示");
                return;
            }

            try
            {
                string sql = "select PictureBox from Tb_pic where ID = '" + this.comboBox1.SelectedItem.ToString() + "'";
                string constring = ConfigurationManager.ConnectionStrings["ConString"].ConnectionString;

                SqlConnection con = new SqlConnection(constring);
                con.Open();
                SqlCommand cmd = new SqlCommand(sql, con);

                string pic = (string)cmd.ExecuteScalar();

                // pic=........这一句换成从数据库里读取就可以了
                //判断是否为空，为空时的不执行
                if (!string.IsNullOrEmpty(pic))
                {
                    //直接返Base64码转成数组
                    byte[] imageBytes = Convert.FromBase64String(pic);
                    //读入MemoryStream对象
                    MemoryStream memoryStream = new MemoryStream(imageBytes, 0, imageBytes.Length);
                    memoryStream.Write(imageBytes, 0, imageBytes.Length);
                    //转成图片
                    Image image = Image.FromStream(memoryStream);

                    //memoryStream.Close();//不要加上这一句否则就不对了

                    // 将图片放置在 PictureBox 中
                    this.pictureBox2.SizeMode = PictureBoxSizeMode.Zoom;
                    this.pictureBox2.Image = image;
                }
            }
            catch { }
        }

        /// <summary>
        /// 取消选中图片事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button4_Click(object sender, EventArgs e)
        {
            arr = null;
            this.pictureBox1.Image = null;
        }
    }
}

参考链接：http://www.sufeinet.com/thread-1261-1-1.html

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