如何从SiteMapNodeCollection中删除节点？

I've got a Repeater that lists all the web.sitemap child pages on an ASP.NET page. Its DataSource is a SiteMapNodeCollection. But, I don't want my registration form page to show up there.

我有一个Repeater,列出了ASP.NET页面上的所有web.sitemap子页面。它的DataSource是一个SiteMapNodeCollection。但是,我不希望我的注册表单显示在那里。

Dim Children As SiteMapNodeCollection = SiteMap.CurrentNode.ChildNodes

'remove registration page from collection
For Each n As SiteMapNode In SiteMap.CurrentNode.ChildNodes
If n.Url = "/Registration.aspx" Then
    Children.Remove(n)
End If
Next

RepeaterSubordinatePages.DataSource = Children

The SiteMapNodeCollection.Remove() method throws a

SiteMapNodeCollection.Remove()方法抛出一个

NotSupportedException: "Collection is read-only".

NotSupportedException:“Collection是只读的”。

How can I remove the node from the collection before DataBinding the Repeater?

在DataBinding Repeater之前,如何从集合中删除节点?

3 个解决方案

#1

Your shouldn't need CType

你不应该需要CType

Dim children = _
    From n In SiteMap.CurrentNode.ChildNodes.Cast(Of SiteMapNode)() _
    Where n.Url <> "/Registration.aspx" _
    Select n

#2

Using Linq and .Net 3.5:

使用Linq和.Net 3.5:

//this will now be an enumeration, rather than a read only collection
Dim children = SiteMap.CurrentNode.ChildNodes.Where( _
    Function (x) x.Url <> "/Registration.aspx" )

RepeaterSubordinatePages.DataSource = children

Without Linq, but using .Net 2:

没有Linq,但使用.Net 2:

Function IsShown( n as SiteMapNode ) as Boolean
    Return n.Url <> "/Registration.aspx"
End Function

...

//get a generic list
Dim children as List(Of SiteMapNode) = _
    New List(Of SiteMapNode) ( SiteMap.CurrentNode.ChildNodes )

//use the generic list's FindAll method
RepeaterSubordinatePages.DataSource = children.FindAll( IsShown )

Avoid removing items from collections as that's always slow. Unless you're going to be looping through multiple times you're better off filtering.

避免从集合中删除项目,因为它总是很慢。除非你要多次循环,否则你最好过滤掉。

#3

I got it to work with code below:

我让它使用下面的代码:

Dim children = From n In SiteMap.CurrentNode.ChildNodes _
               Where CType(n, SiteMapNode).Url <> "/Registration.aspx" _
               Select n
RepeaterSubordinatePages.DataSource = children

Is there a better way where I don't have to use the CType()?

有没有更好的方法我不必使用CType()?

Also, this sets children to a System.Collections.Generic.IEnumerable(Of Object). Is there a good way to get back something more strongly typed like a System.Collections.Generic.IEnumerable(Of System.Web.SiteMapNode) or even better a System.Web.SiteMapNodeCollection?

此外,这会将子项设置为System.Collections.Generic.IEnumerable(Of Object)。是否有一种很好的方法可以获得类似System.Collections.Generic.IEnumerable(Of System.Web.SiteMapNode)更强类型的内容,甚至更好的System.Web.SiteMapNodeCollection?

#1