Question

我的项目中有2个表单。用户无法从frmOptometry中退出第一个。我这样实现了这个：

  Private Sub frmOptometry_FormClosing(sender As Object, e As FormClosingEventArgs) Handles Me.FormClosing
    MessageBox.Show("You can only close the application from the receipt screen!")
    e.Cancel = True
End Sub

第二种形式，frmReceipt可以退出。我用这种方式实现了它：

    Private Sub frmReceipt_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
    If MessageBox.Show("Are you sure you want to quit?",
                       "Obi-Wan Optometry Closing",
                       MessageBoxButtons.YesNo,
                       MessageBoxIcon.Exclamation) =
                   DialogResult.No Then
        e.Cancel = True
    Else
        frmOptometry.Close()
    End If
End Sub

现在，它并没有完全关闭程序，因为它进入frmOptometry_FormClosing并阻止它。我该怎么做才能解决这个问题？无论如何要确定用户试图关闭程序的位置，然后从那里决定？

Answer 1

解决此问题的一种方法是引入flag（例如，称为FromReceipt），表明谁要求frmOptometry关闭自己。

frmOptometry上会发生这样的事情：

Public FromReceipt As Boolean = False 'Add this
Private Sub frmOptometry_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing
    If Not FromReceipt Then 'add this condition
        MessageBox.Show("You can only close the application from the receipt screen!")
        e.Cancel = True
    End If
End Sub

然后在frmReceipt：

Private Sub frmReceipt_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing
    If MessageBox.Show("Are you sure you want to quit?",
                       "Obi-Wan Optometry Closing",
                       MessageBoxButtons.YesNo,
                       MessageBoxIcon.Exclamation) =
                   DialogResult.No Then
        e.Cancel = True
    Else
        frmOptometry.FromReceipt = True 'Add this line to tell the frmOptometry: this time you can really close it
        frmOptometry.Close()
    End If
End Sub

如何关闭第一张表格？

1 个答案: