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

namespace 讀取數(shù)據(jù)庫中的圖片
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        /// <summary>
        /// 選擇圖片
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button1_Click(object sender, EventArgs e)
        {
            //初始化打開文件 對話框
            OpenFileDialog ofdlgTest = new OpenFileDialog();
            ofdlgTest.Filter = "*.jpg|*.png";   //文件過濾 篩選可以打開的文件
            ofdlgTest.Multiselect = false;    //設置不可以選擇多個文件

            //顯示文件打開對話框
            DialogResult result = ofdlgTest.ShowDialog();
            
            //選擇打開按鈕的時候，將文件名顯示到文本框中
            if (result== DialogResult.OK)                   //判斷是否打開文件
            {
                this.textBox1.Text = ofdlgTest.FileName;

                pictureBox1.Image = Image.FromFile(ofdlgTest.FileName);
            }
        }

        /// <summary>
        /// 存入數(shù)據(jù)庫
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button2_Click(object sender, EventArgs e)
        {
            string constr = "Data Source=.;Initial Catalog=MyFirstDatabase;User Id=sa;PassWord=91811372c";

            using(SqlConnection con=new SqlConnection(constr))
            {
                //sql語句  插入圖片
                string sql = "insert into ImageTest values(@UserImage)";
                using(SqlCommand com=new SqlCommand(sql,con))
                {
                    byte[] buffer;   //將圖片轉換為字節(jié)數(shù)組 存入數(shù)據(jù)庫   textBox1.Text 是文件的路徑
                    using(FileStream stream = new FileStream(textBox1.Text, FileMode.OpenOrCreate, FileAccess.Read))
                    {
                        //通過文件路徑 打開文件
                        buffer = new byte[stream.Length];
                        stream.Read(buffer, 0, buffer.Length);  //轉換后 ，存入buffer中
                    }

                    //這個參數(shù) 其實 也沒必要聲明 不過習慣使用 帶參數(shù)的sql語句了 
                    SqlParameter pms = new SqlParameter("@UserImage", SqlDbType.Image) { Value = buffer };
                    com.Parameters.Add(pms);
                    con.Open();
                    string msg = com.ExecuteNonQuery()>0?"存入成功":"存入失敗";
                    MessageBox.Show(msg);
                }
            }
        }

        /// <summary>
        /// 從數(shù)據(jù)庫中讀取
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button3_Click(object sender, EventArgs e)
        {
            string conStr = "Data Source=.;Initial Catalog=MyFirstDatabase;User Id=sa;PassWord=自己的密碼";
            using(SqlConnection con=new SqlConnection(conStr))
            {
                //sql語句
                string sql = "select * from ImageTest";
                using (SqlCommand com = new SqlCommand(sql, con))
                {
                    con.Open();

                   
                   using(SqlDataReader reader=com.ExecuteReader())
                    {
                        if (reader.HasRows)
                        {
                            //聲明一字節(jié)數(shù)組   將數(shù)據(jù)庫中的圖片現(xiàn)存入字節(jié)數(shù)組中
                            byte[] imageByte;
							//在這我是知道里面就一張圖，所以這么寫的，個人根據(jù)實際情況，可做修改
                           while(reader.Read())
                            {
                                //將圖片轉換為字節(jié)數(shù)組
                                imageByte = (byte[])reader["UserImage"];

                                //轉換為文件流
                                MemoryStream stream = new MemoryStream(imageByte);
                                //再將文件流 轉換為 圖像
                                Bitmap bitmap = new Bitmap(stream);
                                pictureBox1.Image = bitmap;
                            }
                        }
                    }
                }
            }
        }
    }
}