当我单击按钮时，Select Case 不会做任何事情

Question

堆栈溢出。 我正在制作一个括号程序。我希望能够使用Select Case 来判断谁会赢。

我做了以下代码：

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim gen1 As New System.Random
        Dim random As Integer
        Dim B1 As String
        random = gen1.Next(0, 101)
        Select Case B1
            Case random <= 50
                MessageBox.Show("less than or = to 50")
            Case random >= 51
                MessageBox.Show("More than or = to 51")
        End Select
    End Sub

但是当我点击按钮时，代码没有做任何事情。没有消息框出现，什么都没有。这段代码可能有什么问题？ 我已经使用Dim gen1 As New System.Random 和Dim random As Integer 正确设置了随机生成器代码，但没有任何反应。感谢您的帮助！

Answer 1

您尚未将 B1 变量设置为任何值。如果你把代码修改成这样：

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim gen1 As New System.Random
    Dim random As Integer
    Dim B1 As String

    random = gen1.Next(0, 101)
    Select Case random
        Case Is <= 50
            MessageBox.Show("less than or = to 50")
        Case Else
            MessageBox.Show("More than or = to 51")
    End Select
End Sub

你可以在这里找到更多信息Select Case Help

您可以改写它以使用 If 语句

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim gen1 As New System.Random

    if gen1.Next(0, 101) <= 50 then
        MessageBox.Show("less than or = to 50")
    else
        MessageBox.Show("More than or = to 51")
    End if
End Sub