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在Asp.Net中從sqlserver檢索(retrieve)圖片

發(fā)表時間：2023-08-17 來源：明輝站整理相關(guān)軟件相關(guān)文章人氣：

[摘要]出處：www.ASPAlliance.com介紹：這篇文章是我寫的"如何把圖片存入sqlServer中"的后續(xù)。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...
出處：www.ASPAlliance.com

介紹：
這篇文章是我寫的"如何把圖片存入sqlServer中"的后續(xù)。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(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>