ASP.NET TreeView和选择所选择的节点 [英] ASP.NET TreeView and Selecting the Selected Node

问题描述

我如何捕捉一个Tr​​eeView的点击所选节点的事件？
它不火的 SelectedNodeChanged 因为选择显然没有改变，但我能赶上那什么大事，所以我知道，选择的节点被点击了？

How do I capture the event of the clicking the Selected Node of a TreeView? It doesn't fire the SelectedNodeChanged since the selection has obviously not changed but then what event can I catch so I know that the Selected Node was clicked?

更新：
当我有一段时间，我将不得不深入到TreeView控件的深处，挖掘出什么，在哪里它处理click事件和子类的TreeView揭露一个新的事件OnSelectedNodeClicked。

UPDATE: When I have some time, I'm going to have to dive into the bowels of the TreeView control and dig out what and where it handles the click events and subclass the TreeView to expose a new event OnSelectedNodeClicked.

我可能会做到这一点在圣诞节假期，我会的结果汇报。

I'll probably do this over the Christmas holidays and I'll report back with the results.

更新：
我想出了低于子类的解决方案TreeView控件。

UPDATE: I have come up with a solution below that sub-classes the TreeView control.

推荐答案

稍长一段之后，我终于有了一些时间来考虑如何继承TreeView的处理所选节点被点击。

After a somewhat lengthy period, I have finally had some time to look into how to subclass the TreeView to handle a Selected Node being clicked.

下面是我的解决方案，它暴露了一个新的事件的 SelectedNodeClicked 您可以从页面或其它地方处理。
（如果需要的话它是一个简单的任务，重构为C＃的）

Here is my solution which exposes a new event SelectedNodeClicked which you can handle from the Page or wherever. (If needed it is a simple task to refactor into C#)

Imports System.Web.UI
Imports System.Web


Public Class MyTreeView
  Inherits System.Web.UI.WebControls.TreeView

  Public Event SelectedNodeClicked As EventHandler

  Private Shared ReadOnly SelectedNodeClickEvent As Object

  Private Const CurrentValuePathState As String = "CurrentValuePath"

  Protected Property CurrentValuePath() As String
    Get
      Return Me.ViewState(CurrentValuePathState)
    End Get
    Set(ByVal value As String)
      Me.ViewState(CurrentValuePathState) = value
    End Set
  End Property

  Friend Sub RaiseSelectedNodeClicked()

    Me.OnSelectedNodeClicked(EventArgs.Empty)

  End Sub

  Protected Overridable Sub OnSelectedNodeClicked(ByVal e As EventArgs)

    RaiseEvent SelectedNodeClicked(Me, e)

  End Sub

  Protected Overrides Sub OnSelectedNodeChanged(ByVal e As System.EventArgs)

    MyBase.OnSelectedNodeChanged(e)

    ' Whenever the Selected Node changed, remember its ValuePath for future reference
    Me.CurrentValuePath = Me.SelectedNode.ValuePath

  End Sub

  Protected Overrides Sub RaisePostBackEvent(ByVal eventArgument As String)

    ' Check if the node that caused the event is the same as the previously selected node
    If Me.SelectedNode IsNot Nothing AndAlso Me.SelectedNode.ValuePath.Equals(Me.CurrentValuePath) Then
      Me.RaiseSelectedNodeClicked()
    End If

    MyBase.RaisePostBackEvent(eventArgument)

  End Sub

End Class

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