C# 图片保存到数据库和从数据库读取图片并显示

Posted 2020-07-10

图片保存到数据库的方法：

        public void imgToDB(string sql)
        {   //参数sql中要求保存的imge变量名称为@images
            //调用方法如：imgToDB("update UserPhoto set [email protected] where UserNo=‘" + temp + "‘");
            FileStream fs = File.OpenRead(t_photo.Text);
            byte[] imageb = new byte[fs.Length];
            fs.Read(imageb, 0, imageb.Length);
            fs.Close();
            SqlCommand com3 = new SqlCommand (sql,con);
            com3.Parameters.Add("@images", SqlDbType.Image).Value = imageb;
            if (com3.Connection.State == ConnectionState.Closed)
                com3.Connection.Open();
            try
            {
                com3.ExecuteNonQuery();
            }
            catch
            { }
            finally
            { com3.Connection.Close(); }
        }

数据库中读出图片并显示在picturebox中：

方法一：
private void ShowImage(string sql)
     {
     //调用方法如：ShowImage("select Photo from UserPhoto where UserNo=‘" + userno +"‘");
     SqlCommand cmd = new SqlCommand(sql, conn);
     conn.Open();
     byte[] b= (byte[])cmd.ExecuteScalar();
     if (b.Length 〉 0)
     {
     MemoryStream stream = new MemoryStream(b, true);
     stream.Write(b, 0, b.Length);
      pictureBox1.Image = new Bitmap(stream);
      stream.Close();
     }
     conn.Close();
     }

方法二：当在dg中选中某行时：
private void dg_MouseUp(object sender, MouseEventArgs e)
        {
            //整行选择
            if (e.Button == System.Windows.Forms.MouseButtons.Left)
            {//用户编号，姓名，性别，身份证号，籍贯，学院，系所，校区，部门，电话，照片
                  //显示相片
                object imgobj=dg[10, dg.CurrentRow.Index].Value;
                if (imgobj != null && !Convert.IsDBNull(imgobj))
                {
                    byte[] imgb = (byte[])imgobj;
                    MemoryStream memStream = new MemoryStream(imgb);
                    try
                    {
                        Bitmap myimge = new Bitmap(memStream);
                        this.pictureBox1.Image = myimge;
                    }
                    catch
                    {
                        DB.msgbox("从数据库读取相片失败！");
                    }
                }
                else
                    pictureBox1.Image = null;
            }

 

使用C#进行图片的数据库存取 
 
 

 

本文总结如何在.Net WinForm和.Net WebForm(asp.net)中将图片存入SQL Server中并读取显示的方法 。 
1.使用asp.net将图片上传并存入SQL Server中，然后从SQL Server中读取并显示出来: 
1)上传并存入SQL Server

数据库结构 
create table test 
{ 
id identity(1,1), 
FImage image 
} 
相关的存储过程 
Create proc UpdateImage 
( 
@UpdateImage Image 
) 
As 
Insert Into test(FImage) values(@UpdateImage) 
GO 
在UpPhoto.aspx文件中添加如下: 
<input id="UpPhoto" name="UpPhoto" runat="server" type="file"> 
<asp:Button id="btnAdd" name="btnAdd" runat="server" Text="上传"></asp:Button> 
然后在后置代码文件UpPhoto.aspx.cs添加btnAdd按钮的单击事件处理代码: 
private void btnAdd_Click(object sender, System.EventArgs e) 
{ 
//获得图象并把图象转换为byte[] 
HttpPostedFile upPhoto=UpPhoto.PostedFile; 
int upPhotoLength=upPhoto.ContentLength; 
byte[] PhotoArray=new Byte[upPhotoLength]; 
Stream PhotoStream=upPhoto.InputStream; 
PhotoStream.Read(PhotoArray,0,upPhotoLength); 
//连接数据库 
SqlConnection conn=new SqlConnection(); 
conn.ConnectionString="Data Source=localhost;Database=test;User Id=sa;Pwd=sa"; 
SqlCommand cmd=new SqlCommand("UpdateImage",conn); 
cmd.CommandType=CommandType.StoredProcedure; 
cmd.Parameters.Add("@UpdateImage",SqlDbType.Image); 
cmd.Parameters["@UpdateImage"].Value=PhotoArray; 
//如果你希望不使用存储过程来添加图片把上面四句代码改为： 
//string strSql="Insert into test(FImage) values(@FImage)"; 
//SqlCommand cmd=new SqlCommand(strSql,conn); 
//cmd.Parameters.Add("@FImage",SqlDbType.Image); 
//cmd.Parameters["@FImage"].Value=PhotoArray; 
conn.Open(); 
cmd.ExecuteNonQuery(); 
conn.Close(); 
} 
2)从SQL Server中读取并显示出来 
在需要显示图片的地方添加如下代码: 
<asp:image id="imgPhoto" runat="server" ImageUrl="ShowPhoto.aspx"></asp:image> 
ShowPhoto.aspx主体代码： 
private void Page_Load(object sender, System.EventArgs e) 
{ 
if(!Page.IsPostBack) 
{ 
SqlConnection conn=new SqlConnection() 
conn.ConnectionString="Data Source=localhost;Database=test;User Id=sa;Pwd=sa"; 
string strSql="select * from test where id=2";//这里假设获取id为2的图片 
SqlCommand cmd=new SqlCommand(strSql,conn); 
conn.Open(); 
SqlDataReader reader=cmd.ExecuteReader(); 
reader.Read(); 
Response.ContentType="application/octet-stream"; 
Response.BinaryWrite((Byte[])reader["FImage"]); 
Response.End(); 
reader.Close(); 
} 
}

2.在WinForm中将图片存入SQL Server，并从SQL Server中读取并显示在picturebox中 
1),存入SQL Server 
数据库结构和使用的存储过过程，同上面的一样 
首先，在窗体中加一个OpenFileDialog控件，命名为ofdSelectPic ； 
然后，在窗体上添加一个打开文件按钮，添加如下单击事件代码： 
Stream ms; 
byte[] picbyte; 
//ofdSelectPic.ShowDialog(); 
if (ofdSelectPic.ShowDialog()==DialogResult.OK) 
{ 
if ((ms=ofdSelectPic.OpenFile())!=null) 
{ 
//MessageBox.Show("ok"); 
picbyte=new byte[ms.Length]; 
ms.Position=0; 
ms.Read(picbyte,0,Convert.ToInt32(ms.Length)); 
//MessageBox.Show("读取完毕!"); 
//连接数据库 
SqlConnection conn=new SqlConnection(); 
conn.ConnectionString="Data Source=localhost;Database=test;User Id=sa;Pwd=sa"; 
SqlCommand cmd=new SqlCommand("UpdateImage",conn); 
cmd.CommandType=CommandType.StoredProcedure; 
cmd.Parameters.Add("@UpdateImage",SqlDbType.Image); 
cmd.Parameters["@UpdateImage"].Value=picbyte; 
conn.Open(); 
cmd.ExecuteNonQuery(); 
conn.Close(); 
ms.Close(); 
} 
} 
2)读取并显示在picturebox中 
首先，添加一个picturebox,名为ptbShow 
然后，添加一个按钮，添加如下响应事件： 
SqlConnection conn=new SqlConnection(); 
conn.ConnectionString="Data Source=localhost;Database=test;User Id=sa;Pwd=sa"; 
string strSql="select FImage from test where id=1"; 
SqlCommand cmd=new SqlCommand(strSql,conn); 
conn.Open(); 
SqlDataReader reader=cmd.ExecuteReader(); 
reader.Read(); 
MemoryStream ms=new MemoryStream((byte[])reader["FImage"]);

Image image=Image.FromStream(ms,true); 
reader.Close(); 
conn.Close(); 
ptbShow.Image=image;