Question

我试过这段代码：

Private Sub TreeView1_AfterCheck(sender As Object, e As TreeViewEventArgs) Handles TreeView1.AfterCheck
        Dim blnUncheck As Boolean = False
        Dim tn As TreeNode
        If e.Node.Nodes.Count = 0 Then
            For Each child As TreeNode In e.Node.Parent.Nodes
                If child.Checked = False Then
                    blnUncheck = True
                End If
            Next
            If blnUncheck = False Then
                e.Node.Parent.Checked = True
            Else
                e.Node.Parent.Checked = False
            End If (the code above is used to check parent when nodes are checked)
            Else (the code below is used to check nodes of parent when parent is checked)
                If e.Node.Checked = True Then
                        For Each tn In e.Node.Nodes
                            tn.Checked = True
                        Next
                    Else
                        For Each tn In e.Node.Nodes
                            tn.Checked = False
                        Next
                    End If
        End If
    End Sub

以便：a）在检查其父级时检查所有节点 b）检查所有节点的父节点

虽然当我从代码中删除其中一个（a，b）时，它会起作用

当我将它们组合在一起时（就像我编写的代码一样），它会引发stackoverflow异常。该代码在树形视图中用于复选框。

编辑：已解决 请访问此链接TreeView.BeforeCheck Event寻求帮助（仔细阅读）

Answer 1

如果您尝试单步执行代码，您会看到每次尝试检查/取消选中某个节点时，都会重新输入该事件。

尝试添加此项检查：

If e.Action = TreeViewAction.Unknown Then
    Exit Sub
End If

如果您没有手动点击（编辑：也适用于按键选择）节点将退出事件并停止无限循环

Answer 2

我认为你正在寻找你可以尝试....

Private Sub CheckAllChildNodes(treeNode As TreeNode, nodeChecked As Boolean)
    Dim node As TreeNode
    For Each node In treeNode.Nodes
        node.Checked = nodeChecked
        If node.Nodes.Count > 0 Then
            Me.CheckAllChildNodes(node, nodeChecked)
        End If
    Next node
End Sub


Private Sub node_AfterCheck(sender As Object, e As TreeViewEventArgs) Handles TreeView1.AfterCheck
    If e.Action <> TreeViewAction.Unknown Then
        If e.Node.Nodes.Count > 0 Then
            Me.CheckAllChildNodes(e.Node, e.Node.Checked)
        Else
            e.Node.Parent.Checked = True
        End If
    End If
End Sub

在检查所有节点时检查父节点，并在检查其父节点时检查所有节点抛出错误

2 个答案: