和存儲(chǔ)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(shí)設(shè)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(xué)習(xí)以下幾個(gè)方面的知識。
·如何設(shè)置圖片的格式？
·如何使用BinaryWrite方法。
我們已經(jīng)在Person表中存儲(chǔ)了數(shù)據(jù)，那么我們就寫些代碼來從表中讀取數(shù)據(jù)。
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(zhí)行一個(gè)sql語句，再循環(huán)讀取所有的記錄（looping through all the records）.
在顯示圖片之前，我們先設(shè)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＞ |
