主题：[讨论]关于下拉窗口直接输入的问题

换个角度看问题，以下是我的通用录入框对于不允许直接输入的控制：

    If e.Form.Controls("TreeView录入树").AllNodes.Count < 1 Then
        MessageBox.Show("没有选择数据")
        e.Form.DropDownBox.Text = ""
    ElseIf e.Form.Controls("TreeView录入树").AllNodes.Count > = 1 Then
        Dim trv As WinForm.TreeView = e.Form.Controls("TreeView录入树")
        Dim i As Integer = 0
        For Each nd As WinForm.TreeNode In trv.AllNodes
            If nd.Level = 0 AndAlso e.Form.DropDownBox.Text = nd.Name Then
                i = i + 1
            End If
        Next
        If i = 0 Then
            MessageBox.Show("没有选择数据")
            e.Form.DropDownBox.Text = ""
        End If
    End If