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＞ |
