如何检测TreeView中是否没有选择节点 [英] How to detect if no node selected in TreeView

问题描述

大家好。

我想知道如何检测用户是否在树视图上没有选择节点。

因为我得到节点名称要做类似





dim id as string



id = TreeView1。 SelectedNode.Name



如果用户没有选择节点，则会出现错误。





这个函数似乎有问题

 公共 功能 NoNodeSelected（ByVal TView  As  TreeView）
 Dim nodes  As  TreeNodeCollection = TView.Nodes 
 Dim n  As  TreeNode 
 对于每个n 在节点
 如果 n .IsSelected 然后 
 NoNodeSelec ted = False 
 结束 如果 
下一个
 NoNodeSelected = True < span class =code-string>' Khôngcónodentnàođượcchọn
'滚动浏览每个Treeview节点
 
 '  For i = 0 To TView.GetNodeCount（True）Step 1 
' < span class =code-keyword>如果 TView.Nodes（i）.IsSelected 那么 
 '  NoNodeSelected = False 
' 结束 如果 
 
 ' 下一个
' 对于每个节点作为 TreeNode 在 TView .Nodes 
 ' 如果Node.IsSelected然后
' NoNodeSelected = False 
 '  结束如果
'下一个
 结束 功能 

只搜索1级。



有人能纠正吗？

解决方案

windows窗体：

使用 TreeView.SelectedNode [ ^ ] property ，获取或设置当前所选Treeview的选定节点。如果当前没有选择TreeNode，则SelectedNode属性为空引用（在Visual Basic中为Nothing）。



要在代码中检查它：

  Dim  tvn  As  System.Windows.Forms.TreeNode =  Me  .TreeView1.SelectedNode 
 MsgBox（ 已选中节点：&（不 tvn   没有）。的ToString）

Hi All.
I Am wondering how to detect if user doesn''t chose the node on a tree view.
Because I get the Node name to do something like


dim id as string

id = TreeView1.SelectedNode.Name

it get error if user doesn''t chose the node.


This function seem to have problem

Public Function NoNodeSelected(ByVal TView As TreeView)
    Dim nodes As TreeNodeCollection = TView.Nodes
    Dim n As TreeNode
    For Each n In nodes
        If n.IsSelected Then
            NoNodeSelected = False
        End If
    Next
    NoNodeSelected = True 'Không có node nào được chọn
    'Scroll through each Treeview Node

    'For i = 0 To TView.GetNodeCount(True) Step 1
    '    If TView.Nodes(i).IsSelected Then
    '        NoNodeSelected = False
    '    End If

    'Next
    'For Each Node As TreeNode In TView.Nodes
    '    If Node.IsSelected Then
    '        NoNodeSelected = False
    '    End If
    'Next
End Function

It only search the level 1.

Can anybody correct it?

解决方案

windows forms:
Use TreeView.SelectedNode[^] property, which get or set selected node for currently selected Treeview. If no TreeNode is currently selected, the SelectedNode property is a null reference (Nothing in Visual Basic).

To check it in code:

Dim tvn As System.Windows.Forms.TreeNode = Me.TreeView1.SelectedNode
MsgBox("Is selected node: " & (Not tvn Is Nothing).ToString)

这篇关于如何检测TreeView中是否没有选择节点的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！