动态树景高度

Question

我的treeview是折叠的，当我加载它，所以它是大约100x150像素大。当它展开时，我希望treeview显示所有展开的节点。

为了做到这一点，窗体需要随着treeview变大而变大，对吗？我是VB.NET的新手，我试图在treeview中找到一个“growonly”属性，但我找不到一个...有人这样做过吗？

Answer 1

添加AfterExpload和AfterConsollabe，使treeview对节点的展开/折叠做出反应。我为这个示例硬编码了填充，但本质上这只是用于调整窗体大小的菜单、按钮等的高度。

Private Sub Rapports_tvAllReports_AfterExpand(sender As Object, e As System.Windows.Forms.TreeViewEventArgs) Handles Rapports_tvAllReports.AfterExpand, Rapports_tvAllReports.AfterCollapse
    Dim Padding As Integer = 140 'Customize this, basically accounts for all buttons or menus included in the form which nests the treeview
    Dim TreeViewHeight As Integer = GetOpenedNodesRecursively(Rapports_tvAllReports)

    If formWindow = FormWindowState.Normal Then Me.Size = New Size(345, TreeViewHeight + Padding)
End Sub

我们所做的就是增加Y并将新的Y设置为形式。为了使treeview与窗体一起正确调整大小，请将其锚定到顶部和底部。

这个函数将通过根节点并在打开的节点上调用递归函数。

Private Function GetOpenedNodesRecursively(ByVal aTreeView As TreeView)
    Dim Y As Integer = 0

    'Go through each node of the treeview (first level)
    For Each n As TreeNode In aTreeView.Nodes
        Y += Rapports_tvAllReports.ItemHeight

        'If the user expands a node, recursively increment the Y
        If n.IsExpanded Then Y += RecursiveYIncrement(n)
    Next

    Return Y
End Function

Private Function RecursiveYIncrement(ByVal n As TreeNode)
    Dim Y As Integer = 0

    'Go through each node of the treeview (first level)
    For Each aNode As TreeNode In n.Nodes
        Y += Rapports_tvAllReports.ItemHeight

        'If the user expands a node, recursively increment the Y
        If aNode.IsExpanded Then Y += RecursiveYIncrement(aNode)
    Next

    Return Y
End Function