ASP_NET ：从SQL Server数据库提取图片并显示在DataGrid.files
和存储图片相比，读取图片就要简单多了。输出一副图片我们要做的就是使用Response对象的BinaryWrite方法。
同时设置图片的格式。在这篇文章中，我们将讨论如何从SqlServer中检索图片。并将学习以下几个方面的知识。
·如何设置图片的格式？
·如何使用BinaryWrite方法。
我们已经在Person表中存储了数据，那么我们就写些代码来从表中读取数据。
下面的代码检索了所有的值从Person表中。
从sqlserver中读取图片的代码。
Public Sub Page_Load(sender As Object, e As EventArgs)
Dim myConnection As New SqlConnection(ConfigurationSettings.AppSettings("ConnectionString"))
Dim myCommand As New SqlCommand("Select * from Person", myConnection)
Try
myConnection.Open()
Dim myDataReader as SqlDataReader
myDataReader = myCommand.ExecuteReader(CommandBehavior.CloseConnection)
Do While (myDataReader.Read())
Response.ContentType = myDataReader.Item("PersonImageType")
Response.BinaryWrite(myDataReader.Item("PersonImage"))
Loop
myConnection.Close()
Response.Write("Person info successfully retrieved!")
Catch SQLexc As SqlException
Response.Write("Read Failed : " & SQLexc.ToString())
End Try
End Sub
看看他是怎么工作的？
上面的例子很简单。我们所作的就是执行一个sql语句，再循环读取所有的记录（looping through all the records）.
在显示图片之前，我们先设置了图片的contentType，然后我们使用BinaryWrite方法把图片输出到浏览器。
源代码：
/// retriving.aspx
<%@ Page Language="vb" %>
<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Data.SqlClient" %>
<HTML>
<HEAD>
<title>Retrieving Image from the Sql Server</title>
<script runat=server>
Public Sub Page_Load(sender As Object, e As EventArgs)
' Create Instance of Connection and Command Object
Dim myConnection As New SqlConnection(ConfigurationSettings.AppSettings("ConnectionString"))
Dim myCommand As New SqlCommand("Select * from Person", myConnection)
Try
myConnection.Open()
Dim myDataReader as SqlDataReader
myDataReader = myCommand.ExecuteReader(CommandBehavior.CloseConnection)
Do While (myDataReader.Read())
Response.ContentType = myDataReader.Item("PersonImageType")
Response.BinaryWrite(myDataReader.Item("PersonImage"))
Loop
myConnection.Close()
Response.Write("Person info successfully retrieved!")
Catch SQLexc As SqlException
Response.Write("Read Failed : " & SQLexc.ToString())
End Try
End Sub
</HEAD>
<body style="font: 10pt verdana">
</body>
</HTML>
