Question

我想编写代码，当单击复选框时，会显示隐藏的组框，然后执行简单的计算。这是我的代码：

Public Class frmMenu
    Private Sub btnCompute_Click(sender As Object, e As EventArgs) Handles btnCompute.Click
        Dim Burgers, Fries, Drinks, sum As Double
        If chkBurgers.Checked Then
            grpBurgers.Visible = True
            If radRegular.Checked Then
                Burgers = 4.19
            ElseIf radWcheese.Checked Then
                Burgers = 4.79
            ElseIf radWbacon.Checked Then
                Burgers = 4.79
            ElseIf radWbcheese.Checked Then
                Burgers = 5.39
            End If
        End If
        If chkFries.Checked Then
            grpFries.Visible = True
            If radSmall.Checked Then
                Fries = 2.39
            ElseIf radMedium.Checked Then
                Fries = 3.09
            ElseIf radLarge.Checked Then
                Fries = 4.99
            End If
        End If
        If chkDrinks.Checked Then
            grpDrinks.Visible = True
            If radSoda.Checked Then
                Drinks = 1.69
            ElseIf radBottled.Checked Then
                Drinks = 1.49
            End If
        End If
        sum = Burgers + Fries + Drinks
        txtCost.Text = sum.ToString("C")
    End Sub
End Class

我用

If chkBurgers.Checked Then
    grpBurgers.Visible = True

显示隐藏的组框，但它在VB 2012中无效，我的代码出了什么问题？对我来说似乎很好。

Answer 1

问题是你在按下按钮时管理可见性，而应该在检查复选框时完成。我会按照以下步骤进行;

Public Class frmMenu

Private Burgers, Fries, Drinks, sum As Double

Private Sub chkBurgers_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles chkBurgers.CheckedChanged


       grpBurgers.Visible = chkBurgers.Checked 
       If chkBurgers.Checked then
        Select case True
         Case radRegular.Checked 
                Burgers = 4.19
         Case radWcheese.Checked  
                Burgers = 4.79
         Case radWbacon.Checked  
                Burgers = 4.79
         Case radWbcheese.Checked  
                Burgers = 5.39
         Case else
                Burgers = 0.00
       End Case

      End If
End Sub

Private Sub chkFries_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles chkFries.CheckedChanged

       grpFries.Visible = chkFries.Checked
       If chkFries.Checked then
        Select case True
         Case radSmall.Checked 
                Fries = 2.39
         Case radMedium.Checked  
                Fries = 3.09
         Case radLarge.Checked  
                Fries = 4.99
         Case else
                Fries = 0.00
       End Case

      End If
 End Sub

 Private Sub chkDrinks_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles chkDrinks.CheckedChanged

      grpDrinks.Visible = chkDrinks.Checked 
       If chkDrinks.Checked then
        Select case True
         Case radSoda.Checked
                Drinks = 1.69
         Case radBottled.Checked  
                Drinks = 1.49 
         Case else
                Fries = 0.00
       End Case

      End If
End Sub

Private Sub btnCompute_Click(sender As Object, e As EventArgs) Handles btnCompute.Click

      sum = Burgers + Fries + Drinks
      txtCost.Text = sum.ToString("C")

End Sub

End Class

为什么这个组隐藏/显示代码不起作用？

1 个答案: