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如何检索SQL 在asp.net

在ASP.NET中从SQL Server检索图片

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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 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

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

Retrieving Image from the Sql ServerPublic 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

 

相关文摘:软件资讯 windows
标题名称:《如何检索SQL 在asp.net》
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