显示数据库中存储的图像

显示数据库中存储的图像

1、给解决方案添加一个新的Windows Forms应用程序项目DisplayDBImages。把Form1.cs更名为DisplayDBImages.cs

2、给窗体添加一个TextBox、一个Button和一个PictureBox

3、给项目添加一个新类Images。代码如下:

using  System;

using  System.Data;

using  System.Data.SqlClient;

using  System.Drawing;

using  System.IO;

namespace  DisplayDBImages

{

     class   Images

    {

         string  strFileName =  null ;

         byte [] imageBytes =  null ;

         SqlConnection  conn =  null   ;

         SqlCommand  cmd =  null ;

         SqlDataReader  reader =  null   ;

         public  Images()

        {

             string  strConn =  @"server=.\MSSQL2012;integrated security=true;initial catalog=tempdb;" ;

            conn =   new   SqlConnection  (strConn);

            cmd =  new   SqlCommand (   @"select imagefile, imagedata from imagetable" , conn);

            conn.Open();

            reader = cmd.ExecuteReader();           

        }

         public   Bitmap  GetImage()

        {

             MemoryStream  ms =  new   MemoryStream   (imageBytes);

             Bitmap  bmp =  new   Bitmap (ms);

             return  bmp;

        }

         public   string  GetFileName()

        {

             return  strFileName;

        }

         // 读取一行记录

         public   bool  GetRow()

        {

             if  (reader.Read())

            {

                strFileName = (   string )reader.GetValue(0);

                imageBytes = (   byte [])reader.GetValue(1);

                 return   true ;

            }

             else

            {

                 return   false ;

            }

        }

         public   void  EndImages()

        {

            reader.Close();

            conn.Close();

        }

    }

}

4、把Images类型的实例变量添加到 DisplayDBImages.Designer.cs中

    private   System.Windows.Forms.  TextBox  textBox1;

     private  System.Windows.Forms.   Button  button1;

     private  System.Windows.Forms.   PictureBox  pictureBox1;

     private   Images  images;

5、记得释放images实例对象。DisplayDBImages.Designer.cs中的DisplayDBImages的Dispose方法中，插入以下代码：

protected   override   void   Dispose( bool   disposing)

{

    images.EndImages();

     if  (disposing && (components !=  null ))

    {               

        components.Dispose();

    }

     base .Dispose(disposing);

}

6、最后，DisplayDBImages.cs的代码如下：

// DisplayDBImages.cs

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;

namespace  DisplayDBImages

{

     public   partial   class   DisplayDBImages  :  Form

    {

         // 显示图片

         private   void  ShowImages()

        {

             if  (images.GetRow())

            {

                 this .textBox1.Text = images.GetFileName();

                 this .pictureBox1.Image = (   Image )images.GetImage();

            }

             else

            {

                 this .textBox1.Text =  "完成"  ;

                 this .pictureBox1.Image =  null ;

            }

        }

         public  DisplayDBImages()

        {

            InitializeComponent();

            images =  new   Images ();

            ShowImages();

        }

       

         private   void  button1_Click(   object  sender,  EventArgs  e)

        {

            ShowImages();

        }       

    }

}

来自为知笔记(Wiz)

转载于:https://www.cnblogs.com/bloodfist/p/3281730.html