Treeview子节点关闭后无法再打开

[Jimmyliu2004]

在Treeview子节点中关闭一个节点，如果再单击就无法打开了，除非选择别的节点后再单击才可以打开。我的事件是afterselect,如果用Click应该如何改呢？代码如下：

Private Sub TreeView_Main_AfterSelect(ByVal sender As System.Object, ByVal e As System.Windows.Forms.TreeViewEventArgs) Handles TreeView_Main.AfterSelect
If Not Me.ActiveMdiChild Is Nothing Then '如果有窗体的话就关闭
Me.ActiveMdiChild.Close()
End If

Select Case e.Node.Text
Case "基础数据"
If rs_usermodel = "零件" Or rs_usermodel = "所有模块" Then '定义权限
Dim frmdatasetup As New FrmDatasetup
frmdatasetup.MdiParent = Me
frmdatasetup.Show()
frmdatasetup.StartPosition = FormStartPosition.CenterParent
frmdatasetup.MaximizeBox = False
Else
MsgBox("权限不够请联系管理员0!", MsgBoxStyle.Information, "Message")
End If

Case "零件录入"
If rs_usermodel = "零件" Or rs_usermodel = "所有模块" Then

If new_frmpart Is Nothing OrElse new_frmpart.IsDisposed Then
Dim new_frmpart As New FrmPart
new_frmpart.Show()
new_frmpart.MdiParent = Me
new_frmpart.WindowState = FormWindowState.Maximized
Else
new_frmpart.Show()
new_frmpart.MdiParent = Me
new_frmpart.WindowState = FormWindowState.Maximized
End If

Else
MsgBox("权限不够请联系管理员!", MsgBoxStyle.Information, "Message")
End If
Case "交易录入"
If rs_usermodel = "交易" Or rs_usermodel = "所有模块" Then
Dim frmtrade_add As New FrmTrade_add
frmtrade_add.MdiParent = Me
frmtrade_add.Show()
frmtrade_add.WindowState = FormWindowState.Maximized
Else
MsgBox("权限不够请联系管理员!", MsgBoxStyle.Information, "Message")
End If

Case "数据查询"
Dim frmsearch As New Frmsearch
frmsearch.MdiParent = Me
frmsearch.Show()
frmsearch.WindowState = FormWindowState.Maximized
frmsearch.MaximizeBox = Fals
End Select
End Sub