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The author:(作者)归海一刀
published in(发表于) 2014/2/1 0:20:08
如何在SQL,Server中保存和输出图片_[SQL,Server教程]

如何在SQL Server中保存和输出图片_[SQL Server教程]

建表   

为了试验这个例子你需要一个含有数据的table(你可以在现在的库中创建它,也可以创建一个新的数据库),下面是它的结构:  


   Column Name 
   Datatype
   Purpose
   ID
   Integer
   identity column Primary key
   imgTITLE
   Varchar(50)
   Stores some user friendly title to identity the image
   imgTYPE
   Varchar(50)
   Stores image content type. This will be same as recognized content types of ASP.NET
   imgDATA
   Image
   Stores actual image or binary data.

保存images进SQL Server数据库  

为了保存图片到table你首先得从客户端上传它们到你的web服务器。你可以创建一个web form,用TextBox得到图片的标题,用HTML File Server Control得到图片文件。确信你设定了Form的encType属性为multipart/form-data。  


   Stream imgdatastream = File1.PostedFile.InputStream; 
   int imgdatalen = File1.PostedFile.ContentLength;
   string imgtype = File1.PostedFile.ContentType;
   string imgtitle = TextBox1.Text;
   byte[] imgdata = new byte[imgdatalen];
   int n = imgdatastream.Read(imgdata,0,imgdatalen);
   string connstr=
   ((NameValueCollection)Context.GetConfig
   ("appSettings"))["connstr"];
   SqlConnection connection = new SqlConnection(connstr);
   SqlCommand command = new SqlCommand
   ("INSERT INTO ImageStore(imgtitle,imgtype,imgdata)
   VALUES ( @imgtitle, @imgtype,@imgdata )", connection );
   SqlParameter paramTitle = new SqlParameter
   ("@imgtitle", SqlDbType.VarChar,50 );
   paramTitle.Value = imgtitle;
   command.Parameters.Add( paramTitle);
   SqlParameter paramData = new SqlParameter
   ( "@imgdata", SqlDbType.Image );
   paramData.Value = imgdata;
   command.Parameters.Add( paramData );
   SqlParameter paramType = new SqlParameter
   ( "@imgtype", SqlDbType.VarChar,50 );
   paramType.Value = imgtype;
   command.Parameters.Add( paramType );
   connection.Open();
   int numRowsAffected = command.ExecuteNonQuery();
   connection.Close();   


从数据库中输出图片   

现在让我们从数据库中取出我们刚刚保存的图片,在这儿,我们将直接将图片输出至浏览器。你也可以将它保存为一个文件或做任何你想做的。

   private void Page_Load(object sender, System.EventArgs e) 
   {
   string imgid =Request.QueryString["imgid"];
   string connstr=((NameValueCollection)
   Context.GetConfig("appSettings"))["connstr"];
   string sql="SELECT imgdata, imgtype FROM ImageStore WHERE id = "
   + imgid;
   SqlConnection connection = new SqlConnection(connstr);
   SqlCommand command = new SqlCommand(sql, connection);
   connection.Open();
   SqlDataReader dr = command.ExecuteReader();
   if(dr.Read())
   {
   Response.ContentType = dr["imgtype"].ToString();
   Response.BinaryWrite( (byte[]) dr["imgdata"] );
   }
   connection.Close();
   }   




在上面的代码中我们使用了一个已经打开的数据库,通过datareader选择images。接着用Response.BinaryWrite代替Response.Write来显示image文件。





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