4

我们有一个网站使用沼泽标准默认站点地图和安全调整,如下所示:

<siteMap defaultProvider="default" enabled="true">
  <providers>
    <add siteMapFile="~/Web.sitemap" securityTrimmingEnabled="true" name="default" type="System.Web.XmlSiteMapProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
  </providers>
</siteMap>

一切都很好,但是已经收到了Title根据某些后端标准更改一个节点的请求。听起来很简单,但显然不是。

尝试 1 - 处理SiteMapResolve事件。在哪里处理这个事件似乎并不重要,我Global.asax只是因为那是我尝试过的地方之一并且它有效,所以我展示了它。

Public Class Global_asax
    Inherits System.Web.HttpApplication

    Sub Application_BeginRequest(ByVal sender As Object, ByVal e As EventArgs)
        AddHandler SiteMap.SiteMapResolve, AddressOf SiteMapResolve
    End Sub

    Sub Application_EndRequest(ByVal sender As Object, ByVal e As EventArgs)
        RemoveHandler SiteMap.SiteMapResolve, AddressOf SiteMapResolve
    End Sub

    Private Shared Function SiteMapResolve(ByVal sender As Object, ByVal e As SiteMapResolveEventArgs) As SiteMapNode

        Dim node As SiteMapNode = SiteMap.CurrentNode
        If IsThisTheNodeToChange(node) Then
            node = node.Clone()
            node.Title = GetNodeTitle()
        End If
        Return node

    End Function

End Class

当导航到相关页面时,这工作正常,但不幸的是,站点导航的一部分涉及一个组合框,该组合框与站点地图数据绑定,如下所示:

<asp:SiteMapDataSource ID="siteMapDataSource" runat="Server" ShowStartingNode="false" StartFromCurrentNode="false" StartingNodeOffset="1" />
<asp:DropDownList ID="pageMenu" runat="Server" AutoPostBack="True" DataSourceID="siteMapDataSource" DataTextField="Title" DataValueField="Url" />

呈现此菜单时,SiteMapResolve不会为任何内容触发事件,因为当前节点是定义菜单的页面。结果,菜单显示物理站点地图文件中的无意义占位符标题,而不是正确的标题。

尝试 2 - 编写我自己的站点地图提供程序。我不想复制所有默认行为,所以我尝试从默认提供程序派生如下。

Public Class DynamicXmlSiteMapProvider
    Inherits XmlSiteMapProvider

    Private _dataFixedUp As Boolean = False

    Public Overrides Function GetChildNodes(ByVal node As SiteMapNode) As SiteMapNodeCollection

        Dim result As SiteMapNodeCollection = MyBase.GetChildNodes(node)
        If Not _dataFixedUp Then
            For Each childNode As SiteMapNode In result
                FixUpNode(childNode)
            Next
        End If
        Return result

    End Function

    Private Sub FixUpNode(ByVal node As SiteMapNode)

        If IsThisTheNodeToChange(node) Then
            node.ReadOnly = False
            node.Title = GetNodeTitle()
            node.ReadOnly = True
            _dataFixedUp = True
        End If

    End Sub

End Class

这不起作用,因为GetChildNodes在网站上导航时似乎并不经常被调用。

尝试 3 - 尝试在数据加载到内存后立即修复数据,而不是在访问数据时修复。

Public Class DynamicXmlSiteMapProvider
    Inherits XmlSiteMapProvider

    Private _dataFixInProgress As Boolean = False
    Private _dataFixDone As Boolean = False

    Public Overrides Function BuildSiteMap() As SiteMapNode

        Dim result As SiteMapNode = MyBase.BuildSiteMap()
        If Not _dataFixInProgress AndAlso Not _dataFixDone Then
            _dataFixInProgress = True
            For Each childNode As SiteMapNode In result.GetAllNodes()
                FixUpNode(childNode)
            Next
            _dataFixInProgress = False
            _dataFixDone = True
        End If
        Return result

    End Function

    Private Sub FixUpNode(ByVal node As SiteMapNode)

        If IsThisTheNodeToChange(node) Then
            node.ReadOnly = False
            node.Title = GetNodeTitle()
            node.ReadOnly = True
        End If

    End Sub

End Class

这似乎有效。但是,我担心方法GetAllNodes中的调用BuildSiteMap。将所有数据递归地拉入内存只是为了修复一个值对我来说似乎是错误的。另外,我无法控制何时BuildSiteMap调用。我更喜欢尝试 1 的东西,它在第一次需要节点数据时按需调用。

尝试 4(新) - 与尝试 2 类似,但覆盖所有与读取数据有关的虚拟成员(CurrentNode, FindSiteMapNode, FindSiteMapNodeFromKey, GetChildNodes, GetCurrentNodeAndHintAncestorNodes, GetCurrentNodeAndHintNeighborhoodNodes, GetParentNode, GetParentNodeRelativeToCurrentNodeAndHintDownFromParent, GetParentNodeRelativeToNodeAndHintDownFromParent, HintAncestorNodes, HintNeighborhoodNodes),以尝试在某处拦截动态节点的读取。

这没有用。我将调试语句放在所有被覆盖的成员中,当数据绑定到下拉列表时,似乎根本没有调用它们。我能想到的唯一解释是在BuildSiteMap调用过程中所有节点都被一次性读入内存,因此SiteMapNode在枚举子节点时不会碰到提供程序类。

有没有人有更好的建议?

4

4 回答 4

2

在我们的自定义 SiteMapProvider 中,我们覆盖 BuildSiteMap 方法并手动构建 SiteMapNodes。要更改和/或添加自定义属性,我们通过创建 NameValueCollection 将自定义属性添加到 SiteMapNodes 并将其添加到 SiteMapNode 构造函数。

于 2009-10-26T12:51:45.923 回答
1

您与尝试 #2 非常接近 - 您还需要覆盖GetParentNodeFindSiteMapNode

于 2009-10-26T12:39:46.057 回答
1

感谢 Mark 和 Rex 的建议。我最终做的是让站点地图提供者一个人呆着,只修复母版页中的一个节点,因此:

Protected Sub Page_Init(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Init

    ' Do this as early as possible in the page lifecycle so that it happens before any
    ' automatic data binding or control initialisation is done.
    Dim node As SiteMapNode = GetNodeToEdit()
    Dim nodeReadOnly As Boolean = node.ReadOnly
    node.ReadOnly = False
    node.Title = GetNodeTitle()
    node.ReadOnly = nodeReadOnly

End Sub

但是,我接受了马克的回答,因为如果事实证明将来需要进行更广泛的修改,我将这样做。

于 2009-11-09T08:56:05.953 回答
1

感谢克里斯蒂安的研究。使用您的结果,我提出了以下可能对其他人有所帮助的建议:

' Dynamically update some menu items.
'
' Since the correct Medical Center ID is not known until runtime, need to
' append "&MEDICAL_CENTER_ID=xxx" to all of the report's URLs in Web.sitemap.
Public Shared Sub UpdateMenu(ByVal MedicalCenterID As String)
  Dim CurrentNodeTitle As String = ""
  Dim NodeReadOnlyProperty As Boolean

  ' Home menu item
  CurrentNodeTitle = SiteMap.CurrentNode.Title

  ' Determines if the current node has child nodes.
  If (SiteMap.CurrentNode.HasChildNodes) Then
    ' Loop through top level 1 menu items (looking for Reports)
    For Each ChildNodesEnumerator1 As SiteMapNode In SiteMap.CurrentNode.ChildNodes
      CurrentNodeTitle = ChildNodesEnumerator1.Title
      If CurrentNodeTitle = "Reports" Then
        ' Loop through level 2 menu items (looking for specfic reports)
        For Each ChildNodesEnumerator2 As SiteMapNode In ChildNodesEnumerator1.ChildNodes
          CurrentNodeTitle = ChildNodesEnumerator2.Title
          If CurrentNodeTitle = "Multi-Day Vehicle Requests" Or _
           CurrentNodeTitle = "XXXXXXXXXXXXXXXXX" Then
            ' First check if the URL has not been modified already
            If InStr(ChildNodesEnumerator2.Url, "MEDICAL_CENTER_ID") = 0 Then
              NodeReadOnlyProperty = ChildNodesEnumerator2.ReadOnly
              ChildNodesEnumerator2.ReadOnly = False
              ChildNodesEnumerator2.Url = ChildNodesEnumerator2.Url & "&MEDICAL_CENTER_ID=" & MedicalCenterID
              ChildNodesEnumerator2.ReadOnly = NodeReadOnlyProperty
            End If
          End If
        Next
      End If
    Next
  End If
End Sub
于 2011-12-16T18:21:54.227 回答