VB运行为什么会出现隐藏的选项？

Question

这个程序是一个考试答题用程序，共5题，运行为什么在第2题会出现“”“NONE”？
代码如下：
相关变量：

Dim tm(0 To 4) As String '当前题目号
Dim xx(0 To 4, 0 To 3) As String '题目是选择题，每题选项最多4个，多出的则为"NONE"
Dim nowd As Integer '当前考生作答题目

错误代码：

'后退按钮相关错误代码
Label3.Caption = tm(nowd)
Check1.Caption = xx(nowd, 0)
Check2.Caption = xx(nowd, 1)
Check3.Caption = xx(nowd, 2)
Check4.Caption = xx(nowd, 3)
If xx(nowd, 2) = "NONE" Then '隐藏含"NONE"的控件
Check3.Visible = False
Check4.Visible = False
Else
If xx(nowd, 3) = "NONE" Then
Check4.Visible = False
End If
End If
If xx(nowd, 2) <> "NONE" Then '显示隐藏的不含"NONE"的控件
Check3.Visible = True
Check4.Visible = True
Else
If xx(nowd, 3) <> "NONE" Then
Check4.Visible = True
End If
End If
End Sub

题目情况:

题目	选项量
1	4
2	3
3	4
4	2
5	3

为什么2题还是显示了"NONE"?谢谢

Answer 1

以下答案参考自ChatGPT。

在 Command2_Click 事件中，你想要显示上一题的选项，并且如果其中一个选项标记为 "NONE"，则隐藏多余的选项。但是你只处理了隐藏的情况，而没有处理显示的情况。这可能导致在从下一题回到上一题时，不会正确显示选项。

在 Command3_Click 事件中，你处理了下一题的逻辑，但是你没有对 "NONE" 选项进行正确的显示和隐藏。这也可能导致在选择了 "NONE" 选项的情况下，下一题的选项不会正确显示。

为了解决这个问题，你可以简化逻辑，只在每次展示新题目时判断 "NONE" 选项是否需要隐藏。我会为你提供一个修复后的代码示例：

Private Sub Command2_Click()
    nowd = nowd - 1
    
    If nowd >= 0 And nowd < 4 Then
        Command3.Visible = True
    End If
    
    If nowd = 0 Then
        Command2.Visible = False
    End If
    
    Label3.Caption = tm(nowd)
    Check1.Caption = xx(nowd, 0)
    Check2.Caption = xx(nowd, 1)
    Check3.Caption = xx(nowd, 2)
    Check4.Caption = xx(nowd, 3)
    
    ' Hide "NONE" options if needed
    If xx(nowd, 2) = "NONE" Then
        Check3.Visible = False
        Check4.Visible = False
    ElseIf xx(nowd, 3) = "NONE" Then
        Check4.Visible = False
    Else
        Check3.Visible = True
        Check4.Visible = True
    End If
End Sub

Private Sub Command3_Click()
    ' ...
    
    nowd = nowd + 1
    
    If nowd >= 0 And nowd < 4 Then
        Command2.Visible = True
    End If
    
    If nowd = 4 Then
        Command3.Visible = False
    End If
    
    Label3.Caption = tm(nowd)
    Check1.Caption = xx(nowd, 0)
    Check2.Caption = xx(nowd, 1)
    Check3.Caption = xx(nowd, 2)
    Check4.Caption = xx(nowd, 3)
    
    ' Hide "NONE" options if needed
    If xx(nowd, 2) = "NONE" Then
        Check3.Visible = False
        Check4.Visible = False
    ElseIf xx(nowd, 3) = "NONE" Then
        Check4.Visible = False
    Else
        Check3.Visible = True
        Check4.Visible = True
    End If
End Sub