在ASP.NET中从SQLServer检索图片

王朝mssql·作者佚名  2008-05-21
窄屏简体版  字體: |||超大  

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)TrymyConnection.Open()Dim myDataReader as SqlDataReadermyDataReader = myCommand.ExecuteReader(CommandBehavior.CloseConnection)Do While (myDataReader.Read())Response.ContentType = myDataReader.Item("PersonImageType")Response.BinaryWrite(myDataReader.Item("PersonImage"))LoopmyConnection.Close()Response.Write("Person info successfully retrieved!")Catch SQLexc As SqlExceptionResponse.Write("Read Failed : " & SQLexc.ToString())End TryEnd 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 ObjectDim myConnection As New SqlConnection(ConfigurationSettings.AppSettings("ConnectionString"))Dim myCommand As New SqlCommand("Select * from Person", myConnection)TrymyConnection.Open()Dim myDataReader as SqlDataReadermyDataReader = myCommand.ExecuteReader(CommandBehavior.CloseConnection)Do While (myDataReader.Read())Response.ContentType = myDataReader.Item("PersonImageType")Response.BinaryWrite(myDataReader.Item("PersonImage"))LoopmyConnection.Close()Response.Write("Person info successfully retrieved!")Catch SQLexc As SqlExceptionResponse.Write("Read Failed : " & SQLexc.ToString())End TryEnd Sub</script></HEAD><body style="font: 10pt verdana"></body></HTML>

 
 
 
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