在Asp.Net中从sqlserver检索(retrieve)图片
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在Asp.Net中从sqlserver检索(retrieve)图片
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介紹：
這篇文章是我寫的"如何把圖片存入sqlServer中"的后續。我建議你在讀這篇文章之前先看看那篇。
和存儲圖片相比，讀取圖片就要簡單多了。輸出一副圖片我們要做的就是使用Response對象的BinaryWrite方法。
同時設置圖片的格式。在這篇文章中，我們將討論如何從SqlServer中檢索圖片。
并將學習以下幾個方面的知識.
·如何設置圖片的格式？
·如何使用BinaryWrite方法。
我們已經在Person表中存儲了數據，那么我們就寫些代碼來從表中讀取數據。
下面的代碼檢索了所有的值從Person表中。
從sqlserver中讀取圖片的代碼.
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？
上面的例子很簡單。我們所作的就是執行一個sql語句，再循環讀取所有的記錄（looping through all the records）.
在顯示圖片之前，我們先設置了圖片的contentType，然后我們使用BinaryWrite方法把圖片輸出到瀏覽器。
源代碼：
/// 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>
這篇文章是我寫的"如何把圖片存入sqlServer中"的后續。我建議你在讀這篇文章之前先看看那篇。
和存儲圖片相比，讀取圖片就要簡單多了。輸出一副圖片我們要做的就是使用Response對象的BinaryWrite方法。
同時設置圖片的格式。在這篇文章中，我們將討論如何從SqlServer中檢索圖片。
并將學習以下幾個方面的知識.
·如何設置圖片的格式？
·如何使用BinaryWrite方法。
我們已經在Person表中存儲了數據，那么我們就寫些代碼來從表中讀取數據。
下面的代碼檢索了所有的值從Person表中。
從sqlserver中讀取圖片的代碼.
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？
上面的例子很簡單。我們所作的就是執行一個sql語句，再循環讀取所有的記錄（looping through all the records）.
在顯示圖片之前，我們先設置了圖片的contentType，然后我們使用BinaryWrite方法把圖片輸出到瀏覽器。
源代碼：
/// 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>
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