c# 读取Northwind数据库image字段

时间：2021-01-16 12:30:54|栏目：.NET代码|点击：次

这里值得一提的是，web控件image不像winForm控件那样可以通过读取二进制流赋值给image属性来显示图像。可以通过变通的方法来实现，流行的做法是新建一个页面专门用来显示图像，这里代码直接用孟子E章前辈的（作了小修改，主要是剔除78个byte字节流来正常显示northwind数据库的图片）：
ReadImage.aspx.cs

复制代码代码如下:

 
using System; 
 
using System.Collections; 
 
using System.Configuration; 
 
using System.Data; 
 
using System.Linq; 
 
using System.Web; 
 
using System.Web.Security; 
 
using System.Web.UI; 
 
using System.Web.UI.HtmlControls; 
 
using System.Web.UI.WebControls; 
 
using System.Web.UI.WebControls.WebParts; 
 
using System.Xml.Linq; 
 
using System.Data.SqlClient; 
 
namespace WebApplication2 
 
{ 
 
public partial class ReadImage : System.Web.UI.Page 
 
{ 
 
protected void Page_Load(object sender, EventArgs e) 
 
{ 
 
string strImageID = Request.QueryString["id"]; 
 
SqlConnection myConnection = new SqlConnection("Data Source=.;Initial Catalog=northwind;User Id=sa;Password=123456;"); 
 
SqlCommand myCommand = new SqlCommand("Select Picture from Categories Where CategoryID=" 
 
+ strImageID, myConnection); 
 
try 
 
{ 
 
myConnection.Open(); 
 
SqlDataReader myDataReader; 
 
myDataReader = myCommand.ExecuteReader(CommandBehavior.CloseConnection); 
 
if (myDataReader.Read()) 
 
{ 
 
Response.Clear(); 
 
Response.ContentType = "image/jpeg"; 
 
byte[] b = (byte[])myDataReader["Picture"]; 
 
//下面的方法就是用来让图片可以正常显示 
 
byte[] temp=new byte [b.Length -78]; 
 
Array.Copy(b, 78, temp, 0, b.Length - 78); 
 
Response.BinaryWrite(temp); 
 
} 
 
myConnection.Close(); 
 
} 
 
catch (SqlException SQLexc) 
 
{ 
 
Response.Write(SQLexc.ToString ()); 
 
} 
 
Response.End(); 
 
} 
 
} 
 
}

在源页面如Default.aspx.cs可以通过下面方法调用

复制代码代码如下:

 
protected void Page_Load(object sender, EventArgs e) 
 
{ 
 
if(!IsPostBack ) 
 
Image1.ImageUrl = FormatURL("1"); 
 
} 
 
protected string FormatURL(string strArgument) 
 
{ 
 
return "ReadImage.aspx?id=" + strArgument; 
 
}

如果不想新建一个页面来承载图像，也可以使用下面的方法：（注意：下面的类是自定义的，大家看得懂这个方法就可以了）

复制代码代码如下:

 
using System; 
 
using System.Collections; 
 
using System.Configuration; 
 
using System.Data; 
 
using System.Linq; 
 
using System.Web; 
 
using System.Web.Security; 
 
using System.Web.UI; 
 
using System.Web.UI.HtmlControls; 
 
using System.Web.UI.WebControls; 
 
using System.Web.UI.WebControls.WebParts; 
 
using System.Xml.Linq; 
 
using System.Data.SqlClient; 
 
namespace WebApplication2 
 
{ 
 
public partial class ReadImage : System.Web.UI.Page 
 
{ 
 
protected void Page_Load(object sender, EventArgs e) 
 
{ 
 
string strImageID = Request.QueryString["id"]; 
 
SqlConnection myConnection = new SqlConnection("Data Source=.;Initial Catalog=northwind;User Id=sa;Password=123456;"); 
 
SqlCommand myCommand = new SqlCommand("Select Picture from Categories Where CategoryID=" 
 
+ strImageID, myConnection); 
 
try 
 
{ 
 
myConnection.Open(); 
 
SqlDataReader myDataReader; 
 
myDataReader = myCommand.ExecuteReader(CommandBehavior.CloseConnection); 
 
if (myDataReader.Read()) 
 
{ 
 
Response.Clear(); 
 
Response.ContentType = "image/jpeg"; 
 
byte[] b = (byte[])myDataReader["Picture"]; 
 
byte[] temp=new byte [b.Length -78]; 
 
Array.Copy(b, 78, temp, 0, b.Length - 78); 
 
Response.BinaryWrite(temp); 
 
} 
 
myConnection.Close(); 
 
} 
 
catch (SqlException SQLexc) 
 
{ 
 
Response.Write(SQLexc.ToString ()); 
 
} 
 
Response.End(); 
 
} 
 
} 
 
}

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