Question

我有一个非常奇怪的问题。我正在创建一个网页，从数据库中检索链接列表并显示它们。我检索记录并将它们加载到对象列表中。但是，当我稍后遍历该列表时，我将显示重复的项目。

查看结果的页面为http://myhacc.azurewebsites.net/testlinks.aspx

每个链接应该只有1个，你可以看到每个链接中有2个。我不知道为什么。我已经超过了我的逻辑10次。

我正在使用在microsoft azure上运行的Microsoft SQL Server 网页也作为网络应用程序托管在microsoft azure上。

我检查了我的数据库，数据库中没有重复的条目。数据库的结构如下

表：myportal_lcat 字段：id - 整数字段：名称 - 文本

表：myportal_lhref 字段：catid - 整数字段：dname - 文本字段：href - text

代码如下

<%@ Page Title="" Language="VB" MasterPageFile="~/Main.master" %>

<script runat="server">
    Private oCon As Data.SqlClient.SqlConnection
    Private oCon2 As Data.SqlClient.SqlConnection
    Private oCatCom As New Data.SqlClient.SqlCommand
    Private oCatRead As Data.SqlClient.SqlDataReader
    Private oItemCom As New Data.SqlClient.SqlCommand
    Private oItemRead As Data.SqlClient.SqlDataReader
    Private liLinks As New List(Of linkItem)

    Private Sub Page_Load() Handles Me.Load
        oCon = New Data.SqlClient.SqlConnection("Server=xxxx,1433;Database=xxxxx;User ID=xxxxxx;Password=xxxxx;Encrypt=True;TrustServerCertificate=False;Connection Timeout=30;")
        oCon2 = New Data.SqlClient.SqlConnection("Server=xxxxxx,1433;Database=xxxx;User ID=xxxx;Password=xxxxx;Encrypt=True;TrustServerCertificate=False;Connection Timeout=30;")
        oCon.Open()
        oCon2.Open()
        oCatCom.Connection = oCon
        oCatCom.CommandText = "Select * From myportal_lcat"
        oItemCom.Connection = oCon2
        oItemCom.CommandText = "Select * From myportal_lhref"
        oCatRead = oCatCom.ExecuteReader()
        oItemRead = oItemCom.ExecuteReader()
        Do While oItemRead.Read
            liLinks.Add(New linkItem With {.CatID = oItemRead("catid"), .DName = oItemRead("dname"), .HREF = oItemRead("href")})
        Loop
    End Sub

    Private Class linkItem
        Private m_CatID As Integer
        Private m_DName As String
        Private m_HREF As String
        Public Property CatID() As Integer
            Get
                CatID = m_CatID
            End Get
            Set(value As Integer)
                m_CatID = value
            End Set
        End Property
        Public Property DName() As String
            Get
                DName = m_DName
            End Get
            Set(value As String)
                m_DName = value
            End Set
        End Property
        Public Property HREF() As String
            Get
                HREF = m_HREF
            End Get
            Set(value As String)
                m_HREF = value
            End Set
        End Property
    End Class
</script>

<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server">
    My Portal - Test
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="PageHeader" Runat="Server">
</asp:Content>
<asp:Content ID="Content3" ContentPlaceHolderID="PageContent" Runat="Server">
    <%Dim t As linkItem %>
    <%Do While oCatRead.Read()%>
        <section class="links">
            <h2><%=oCatRead("name") %></h2>
            <ul>
                <%For each t In liLinks %>
                    <%If t.CatID = oCatRead("id") Then %>
                        <li><a href="<%=t.HREF %>"><%=t.DName %></a></li>
                    <%End If %>
                <%Next %>
            </ul>
        </section>
    <%Loop%>
</asp:Content>

Answer 1

问题是由于当使用asp.net主页时，首先在主页中调用page_load，然后再在实际页面中调用。但是，两者的代码都运行了两次。

当我在页面加载中将项目添加到列表时初始化声明中的对象列表时，因为page_load运行了两次，所以添加了两次。我将对象列表的初始化移动到page_load而不是声明，这解决了我的问题。

参考：Page_Load is firing twice in ASP.NET page

显示数据库信息时显示的重复条目 - VB.Net ASP.Net

1 个答案: