知识大全在ASP.net 中从sqlserver检索(retrieve)图片

Posted 2022-07-16 知

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　　 一介绍　　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　　１．如何设置图片的格式？　　２．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)TrymyConnection 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 SqlExceptionResponse Write( Read Failed : & SQLexc ToString())End TryEnd Sub

　　二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 ObjectDim myConnection As New SqlConnection(ConfigurationSettings AppSettings( ConnectionString ))Dim myCommand As New SqlCommand( Select * from Person myConnection)TrymyConnection 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 SqlExceptionResponse Write( Read Failed : & SQLexc ToString())End TryEnd Sub

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知识大全 在ASP.net 中从sqlserver检索(retrieve)图片

知识大全在ASP.net 中从sqlserver检索(retrieve)图片