Question

我正在尝试创建一个类似于以下内容的树视图：

父

| __的 Child1

| __ __ __ O 孙子1

| __ __ __ O 孙子2

| __的 CHILD2

| __ __ __ O 孙子3

| __ __ __ O 孙子4

我在Visual Studio 2008中使用vb.net。非常感谢有关如何实现这一点的任何见解！

Answer 1

您不能在TreeView中使用单选按钮，只能使用复选框。

解决方案是使复选框的行为类似于单选按钮：

Private Sub TreeView1_AfterCheck(ByVal sender As System.Object, ByVal e As System.Windows.Forms.TreeViewEventArgs) Handles TreeView1.AfterCheck
    If e.Node.Checked Then
        If e.Node.Level = 2 Then
            For Each node As TreeNode In e.Node.Parent.Nodes
                If node IsNot e.Node Then
                    node.Checked = False
                End If
            Next
        Else
            e.Node.Checked = False
        End If
    End If
End Sub

e.Node.Level = 2检查确保只有孙子节点的行为类似于单选按钮。

将TreeView的CheckBoxes属性设置为True以启用复选框。

这是如何更改所选节点及其父节点的文本样式的示例：

Private Sub TreeView1_BeforeSelect(ByVal sender As System.Object, ByVal e As System.Windows.Forms.TreeViewCancelEventArgs) Handles TreeView1.BeforeSelect
    If TreeView1.SelectedNode IsNot Nothing Then
        MakeSelected(TreeView1.SelectedNode, False)
    End If
    MakeSelected(e.Node, True)
End Sub

Private Sub MakeSelected(ByVal node As TreeNode, ByVal selected As Boolean)
    Dim SelectedFont As New Font(TreeView1.Font, FontStyle.Bold)
    node.NodeFont = IIf(selected, SelectedFont, TreeView1.Font)
    node.ForeColor = IIf(selected, Color.Blue, TreeView1.ForeColor)

    If node.Parent IsNot Nothing Then
        MakeSelected(node.Parent, selected)
    End If
End Sub

它递归地更改所选节点及其父节点的文本样式，并在选择更改时将其设置回TreeView的默认样式。

Answer 2

 Public Sub getAFCategories(selectedId As String)
        Dim cn As Data.SqlClient.SqlConnection
        cn = New Data.SqlClient.SqlConnection(ConfigurationManager.AppSettings("ConnStr"))
        Try
            Dim MerchantSiteId As String = get_MerchantSiteID()
            Dim da As SqlDataAdapter
            Dim dt As New DataTable
            Dim cmd As New SqlCommand()
            cmd.Connection = cn
            cmd.CommandType = CommandType.Text
            cmd.CommandText = "SELECT categoryId, Category, ParentId FROM tblCategories"
            cn.Open()
            da = New SqlDataAdapter(cmd)
            da.Fill(dt)
            TrViewAfCategories.Nodes.Clear()
            Me.PopulateTreeView2(dt, 0, Nothing, dt, selectedId)
        Catch ex As Exception
        Finally
            cn.Close()
        End Try

    End Sub

 Private Sub PopulateTreeView2(dtParent As DataTable, parentId As Integer, treeNode As TreeNode, dtMain As DataTable, selectedId As String)
        Dim redindex As Integer = 1
        For Each row As DataRow In dtParent.Rows
            Dim child As New TreeNode() With { _
             .Text = row("Category").ToString(), _
             .Value = row("AFCategoryId").ToString() _
            }
            If row("ParentId").ToString() = 0 Then
                TrViewAfCategories.Nodes.Add(child)
                redindex = parentId + redindex
                Dim dtChild As DataTable = Me.GetFilterData(dtMain, child.Value) 'Me.getData("SELECT AFCategoryId, Category, ParentId FROM tblAFFeedCategories WHERE ParentId = " + child.Value)
                PopulateTreeView2(dtChild, redindex, child, dtMain, selectedId)
            Else
                If parentId = 1 Then
                    child.ShowCheckBox = False
                    Dim dtChild As DataTable = Me.GetFilterData(dtMain, child.Value)
                    If dtChild.Rows.Count = 0 Then
                        If (selectedId = child.Text) Then
                            child.Text = "<input type='radio' name='rdoC" + row("AFCategoryId").ToString() + "' value ='" + row("Category").ToString() + "'  checked='checked'/>" + child.Text
                        Else
                            child.Text = "<input type='radio' name='rdoC" + row("AFCategoryId").ToString() + "' value ='" + row("Category").ToString() + "' />" + child.Text
                        End If
                    End If
                    treeNode.ChildNodes.Add(child)
                    'Me.getData("SELECT AFCategoryId, Category, ParentId FROM tblAFFeedCategories WHERE ParentId = " + child.Value)
                    PopulateTreeView2(dtChild, parentId, child, dtMain, selectedId)
                End If
            End If

        Next
    End Sub
 Private Function GetFilterData(parentData As DataTable, filterValue As String) As DataTable
        Dim dt As New DataTable()
        Dim dvFilter As New DataView
        dvFilter = parentData.DefaultView
        dvFilter.RowFilter = Nothing
        dvFilter.RowFilter = "ParentId = " & filterValue
        dt = dvFilter.ToTable()
        Return dt
    End Function

如何在[grand]子节点中使用单选按钮创建树视图？

2 个答案: