SiteMap.SiteMapResolve 事件

定义

命名空间:

System.Web

程序集:

System.Web.dll

当访问 CurrentNode 属性时发生。

public:
 static event System::Web::SiteMapResolveEventHandler ^ SiteMapResolve;

public static event System.Web.SiteMapResolveEventHandler SiteMapResolve;

member this.SiteMapResolve : System.Web.SiteMapResolveEventHandler 

Public Shared Custom Event SiteMapResolve As SiteMapResolveEventHandler 

事件类型

SiteMapResolveEventHandler

示例

下面的代码示例演示如何处理 SiteMapResolve ASP.NET 网页上的事件，以修改网站导航控件（如 SiteMapPath 控件）显示的目标 URL。 在此示例中，当前页面是在线公告板或论坛中的帖子页。 为了呈现更有意义的网站导航，导航控件显示的节点的 URL 追加了上下文相关查询字符串。

注意

ASP.NET 站点导航基础结构可防止无限递归，从而提供安全保障，并最大程度地降低与从 类内部SiteMapResolveEventHandler访问CurrentNode属性相关的安全风险。

以下代码属于 Global.asax 文件。 对于应用程序，事件处理程序只会附加一次。 代码识别页面是否实现 接口 ISiteMapResolver 。 如果实现接口，则 ExpandForumPaths 调用 函数。

private void Page_Load(object sender, EventArgs e)
{
    // The ExpandForumPaths method is called to handle
    // the SiteMapResolve event.
    SiteMap.SiteMapResolve +=
      new SiteMapResolveEventHandler(this.ExpandForumPaths);
}

private SiteMapNode ExpandForumPaths(Object sender, SiteMapResolveEventArgs e)
{
    // The current node represents a Post page in a bulletin board forum.
    // Clone the current node and all of its relevant parents. This
    // returns a site map node that a developer can then
    // walk, modifying each node.Url property in turn.
    // Since the cloned nodes are separate from the underlying
    // site navigation structure, the fixups that are made do not
    // effect the overall site navigation structure.
    SiteMapNode currentNode = SiteMap.CurrentNode.Clone(true);
    SiteMapNode tempNode = currentNode;

    // Obtain the recent IDs.
    int forumGroupID = GetMostRecentForumGroupID();
    int forumID = GetMostRecentForumID(forumGroupID);
    int postID = GetMostRecentPostID(forumID);

    // The current node, and its parents, can be modified to include
    // dynamic querystring information relevant to the currently
    // executing request.
    if (0 != postID)
    {
        tempNode.Url = tempNode.Url + "?PostID=" + postID.ToString();
    }

    if ((null != (tempNode = tempNode.ParentNode)) &&
        (0 != forumID))
    {
        tempNode.Url = tempNode.Url + "?ForumID=" + forumID.ToString();
    }

    if ((null != (tempNode = tempNode.ParentNode)) &&
        (0 != forumGroupID))
    {
        tempNode.Url = tempNode.Url + "?ForumGroupID=" + forumGroupID.ToString();
    }

    return currentNode;
}

Private Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)

    ' The ExpandForumPaths method is called to handle
    ' the SiteMapResolve event.
    AddHandler SiteMap.SiteMapResolve, AddressOf Me.ExpandForumPaths

End Sub

Private Function ExpandForumPaths(ByVal sender As Object, ByVal e As SiteMapResolveEventArgs) As SiteMapNode
    ' The current node represents a Post page in a bulletin board forum.
    ' Clone the current node and all of its relevant parents. This
    ' returns a site map node that a developer can then
    ' walk, modifying each node.Url property in turn.
    ' Since the cloned nodes are separate from the underlying
    ' site navigation structure, the fixups that are made do not
    ' effect the overall site navigation structure.
    Dim currentNode As SiteMapNode = SiteMap.CurrentNode.Clone(True)
    Dim tempNode As SiteMapNode = currentNode

    ' Obtain the recent IDs.
    Dim forumGroupID As Integer = GetMostRecentForumGroupID()
    Dim forumID As Integer = GetMostRecentForumID(forumGroupID)
    Dim postID As Integer = GetMostRecentPostID(forumID)

    ' The current node, and its parents, can be modified to include
    ' dynamic querystring information relevant to the currently
    ' executing request.
    If Not (0 = postID) Then
        tempNode.Url = tempNode.Url & "?PostID=" & postID.ToString()
    End If

    tempNode = tempNode.ParentNode
    If Not (0 = forumID) And Not (tempNode Is Nothing) Then
        tempNode.Url = tempNode.Url & "?ForumID=" & forumID.ToString()
    End If

    tempNode = tempNode.ParentNode
    If Not (0 = ForumGroupID) And Not (tempNode Is Nothing) Then
        tempNode.Url = tempNode.Url & "?ForumGroupID=" & forumGroupID.ToString()
    End If

    Return currentNode

End Function

以下代码定义一个单独的接口。 (在网站项目中，可以将此代码放入 App_Code 文件夹。) 接口 ISiteMapResolver 定义 ExpandForumPaths 方法。

// These methods are just placeholders for the example.
// One option is to use the HttpContext or e.Context object
// to obtain the ID.
private int GetMostRecentForumGroupID()
{
    return 24;
}

private int GetMostRecentForumID(int forumGroupId)
{
    return 128;
}

private int GetMostRecentPostID(int forumId)
{
    return 317424;
}

' These methods are just placeholders for the example.
' One option is to use the HttpContext or e.Context object
' to obtain the ID.
Private Function GetMostRecentForumGroupID() As Integer
    Return 24
End Function

Private Function GetMostRecentForumID(ByVal forumGroupId As Integer) As Integer
    Return 128
End Function

Private Function GetMostRecentPostID(ByVal forumId As Integer) As Integer
    Return 317424
End Function

以下代码属于站点地图结构中至少三个节点的页面。 页面实现 ISiteMapResolver 接口，该接口允许 ExpandForumPaths 调用 方法。

<asp:SiteMapPath
id="SiteMapPath1"
runat="server"
RenderCurrentNodeAsLink="true" />

<asp:SiteMapPath
id="SiteMapPath1"
runat="server"
RenderCurrentNodeAsLink="true" />

注解

订阅服务器将对象附加到 SiteMapResolveEventHandler 静态 SiteMapResolve 事件，以在访问 属性时 CurrentNode 接收通知。 这使用户能够在创建 SiteMapNode 当前正在执行的页的表示形式时实现自定义逻辑，而无需自定义提供程序实现。

如果订阅事件 SiteMapResolve ，则还会订阅 SiteMapResolve 默认站点地图提供程序上的事件。

另请参阅

• SiteMapResolveEventHandler
• SiteMapResolveEventArgs