Question

我有正确的代码。当我按下是的命令将执行但当我按下否则不退出它仍然执行命令..有人可以帮助我？我是vb编程的新手......（对不起英文）

继承人的代码

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim payed As Integer
        Dim balance As Integer
        Dim paying As Integer
        Dim d As Integer
        Dim c As Integer
        Try

            Dim ans As Integer
            If TextBox7.Text = "" Or 0 Then

                MsgBox("please enter amount", MsgBoxStyle.Critical)
            Else
                If TextBox6.Text = 0 Then

                    MsgBox("the student is fully payed", MsgBoxStyle.Critical)
                Else
                    ans = MsgBox(" are you want to upadate the students payment? ", MsgBoxStyle.YesNo, "confirm ")
                    If MsgBoxResult.Yes Then


                        payed = Val(TextBox5.Text)
                        balance = Val(TextBox6.Text)
                        paying = Val(TextBox7.Text)
                        d = payed + paying
                        c = balance - paying
                        TextBox5.Text = d
                        TextBox6.Text = c

                        Dim SqlQuery = "UPDATE sample SET [Payed Amount] ='" & TextBox5.Text & "',Balance ='" & TextBox6.Text & "' WHERE ID = " & a & " ; "
                        Dim sqlcommand As New OleDbCommand
                        With sqlcommand
                            .CommandText = SqlQuery
                            .Connection = conn
                            .ExecuteNonQuery()
                        End With
                        MsgBox("student payment succesfully updated")
                        My.Computer.Audio.Play(My.Resources.CASHREG, AudioPlayMode.Background)
                        If TextBox6.Text = 0 Then
                            MsgBox("the student is now fully paid", MsgBoxStyle.Information)
                            TextBox7.Text = ""
                        Else

                            MsgBox("students current balance is " & Convert.ToString(TextBox6.Text))
                            LoadListView()
                            TextBox7.Text = ""
                        End If
                    Else
                        Exit Sub
                    End If
                End If
            End If
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try

Answer 1

这是您的代码的一部分：

ans = MsgBox(" are you want to upadate the students payment? ", MsgBoxStyle.YesNo, "confirm ")
If MsgBoxResult.Yes Then

您要将消息框调用的结果分配给ans，但实际上您并未测试 ans的值。当你说

If MsgBoxResult.Yes Then

这将始终为真，因为MsgBoxResult.Yes是一个常量值，始终为True。你真的希望这个测试是

If ans = MsgBoxResult.Yes Then

虽然VB.NET不是我的强项，但我对你所编写的内容感到有些惊讶。我建议你总是在你的代码中使用Option Strict，我认为这会在编译时将其显示为一个问题。

如何使用MSGBOX是否

1 个答案: