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介绍：
这篇文章是我写的"如何把图片存入sqlserver中"的后续。我建议你在读这篇文章之前先看看那篇。
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
</script>
</head>
<body style="font: 10pt verdana">
</body>
</html>
