蛇和梯子

Question

我必须为项目创建一个蛇和梯子游戏。我的电路板上有30个空格。如果标记超过30，则应用程序崩溃：

“appCounter.exe中发生了'System.NullReferenceException'类型的未处理异常

附加信息：对象引用未设置为对象的实例。“

如果滚动的数字超过30，我希望标记保持原样。

这是我的代码：

Public Class frmBoard
Dim intScore As Integer

Private Sub btnOK_Click(sender As Object, e As EventArgs) Handles btnOK.Click
    'declartions
    Dim intValue As Integer
    Dim strCounterName As String
    Dim roll As New Random()
    Dim intRoll = roll.Next(1, 7)

    'make the current counter visible
    If intScore > 0 Then
        strCounterName = "lblCounter" & intScore
        Me.Controls(strCounterName).Visible = False
    End If


    'input
    intValue = intRoll
    intScore = intScore + intValue
    strCounterName = "lblcounter" & intScore.ToString

    'output
    txtMove.Text = intRoll
    Me.Controls(strCounterName).Visible = True

    If intScore = 3 Then
        lblCounter3.Visible = False
        lblCounter22.Visible = True
        intScore = 22
    End If

    If intScore = 5 Then
        lblCounter5.Visible = False
        lblCounter8.Visible = True
        intScore = 8
    End If

    If intScore = 11 Then
        lblCounter11.Visible = False
        lblCounter26.Visible = True
        intScore = 26
    End If

    If intScore = 20 Then
        lblCounter20.Visible = False
        lblCounter29.Visible = True
        intScore = 29
    End If

    If intScore = 17 Then
        lblCounter17.Visible = False
        lblCounter4.Visible = True
        intScore = 4
    End If

    If intScore = 19 Then
        lblCounter19.Visible = False
        lblCounter7.Visible = True
        intScore = 7
    End If

    If intScore = 21 Then
        lblCounter21.Visible = False
        lblCounter9.Visible = True
        intScore = 9
    End If

    If intScore = 27 Then
        lblCounter27.Visible = False
        lblCounter1.Visible = True
        intScore = 1
    End If

    If intScore = 31 Then
        lblCounter31.Visible = False
        lblCounter1.Visible = True
        intScore = 1
    End If

    If intScore = 32 Then
        lblCounter32.Visible = False
        lblCounter1.Visible = True
        intScore = 1
    End If

    If intScore = 33 Then
        lblCounter33.Visible = False
        lblCounter1.Visible = True
        intScore = 1
    End If

    If intScore = 30 Then
        MsgBox("Winner")
    End If

    If intScore > 30 Then
        MsgBox("OvErBoArD")
    End If
    End Sub


End Class

Answer 1

这将向您的用户显示他们已经过去并跳过将总计添加到总数中以使其保留到位。

变化：

'input
intValue = intRoll
intScore = intScore + intValue
strCounterName = "lblcounter" & intScore.ToString

要：

'input
intValue = intRoll
If intScore + intValue > 30 Then
    MsgBox "OvErBoArD"
Else
    intScore = intScore + intValue
End If
strCounterName = "lblcounter" & intScore.ToString

Answer 2

由于当intScore超过30时只有30个计数器，因此会抛出此异常。

在输入中添加If语句，如下所示：

'input
intValue = intRoll
If intscore + intvalue < 30 then 
intscore=intscore + intvalue
End if

strCounterName = "lblcounter" & intScore.ToString

这样它在设置lblcounter之前不会超过30，并且不会出错