Question

所以我正在尝试创建一个基于菜单选项创建订单的应用程序。菜单使用组合框，然后我使用组合框选项添加总数的数字。但是，组合框的默认值为空，我希望它为“0”。如何在不覆盖用户选择的情况下将所选索引更改为0而不是减1。我的代码：

Public Class addOrder

  Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

    Dim A = Convert.ToInt32(margQty.Text) * 9.5
    Dim B = Convert.ToInt32(hawQty.Text) * 10.5
    Dim C = Convert.ToInt32(pepQty.Text) * 10.5
    Dim D = Convert.ToInt32(pepDelQty.Text) * 11.5
    Dim E1 = Convert.ToInt32(pineQty.Text) * 0.5
    Dim F = Convert.ToInt32(hamQty.Text) * 0.5
    Dim G = Convert.ToInt32(cheQty.Text) * 1.0
    Dim H = Convert.ToInt32(exPepQty.Text) * 0.5
    Dim SubTot As Double = (A + B + C + D + E1 + F + G + H)
    Dim Tot As String = (SubTot) * 1.2

    MsgBox("The order sub total total is: £" + Str(SubTot) & vbCrLf & "The order total is £" + Tot)

  End Sub

End Class

Answer 1

在Form Load事件期间（双击IDE中的表单），填充组合框，然后使用它来设置默认索引：

e.g：

Private Sub frmName_Load(ByVal sender As Object, ByVal e As System.EventArgs) Me.Load

'Load/call whatever you'd like for this particular form
'...

'Populate your combo box through a list or manually
'... 

'Set the default selected index:
If YourComboBox.Items.Count > 0
    YourComboBox.SelectedIndex = 0

End Sub

更改组合框的默认值

1 个答案: