在ASP.NET中从SQL Server检索图片 (1)

　　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 : " %26amp; 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

%26lt;%@ Page Language="vb" %%26gt;
%26lt;%@ Import Namespace="System.Data" %%26gt;
%26lt;%@ Import Namespace="System.Data.SqlClient" %%26gt;
%26lt;HTML%26gt;
%26lt;HEAD%26gt;
%26lt;title%26gt;Retrieving Image from the Sql Server%26lt;/title%26gt;
%26lt;script runat=server%26gt;
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 : " %26amp; SQLexc.ToString())
End Try
End Sub

%26lt;/script%26gt;
%26lt;/HEAD%26gt;
%26lt;body style="font: 10pt verdana"%26gt;
%26lt;/body%26gt;
%26lt;/HTML%26gt;