Vb.net 如何更改IF语句以选择…Case

我已经得到了以下内容，其中包含了一个特定变量的多个值，我不想用大量的

IF-ELSE

语句来处理它们，因此如果有人能够非常友好地使用

SELECT-CASE

语句来修改代码，我将不胜感激

另外，我希望

dgMarksEntry.Item（7，I）.Value

和

dgMarksEntry.Item（8，I）.Value

分别处理

RANK

和

COUNT

输入的项目数

 For i = 0 To 100
        dgMarksEntry.Item(4, i).Value = Val(dgMarksEntry.Item(3, i).Value) + Val(dgMarksEntry.Item(2, i).Value)

        If dgMarksEntry.Item(4, i).Value >= 80 Then
            dgMarksEntry.Item(5, i).Value = "A1"
            dgMarksEntry.Item(6, i).Value = "Excellent"
        ElseIf dgMarksEntry.Item(4, i).Value >= 75 Then
            dgMarksEntry.Item(5, i).Value = "B2"
            dgMarksEntry.Item(6, i).Value = "Very good"
        ElseIf dgMarksEntry.Item(4, i).Value >= 70 Then
            dgMarksEntry.Item(5, i).Value = "B3"
            dgMarksEntry.Item(6, i).Value = "Good"
        ElseIf dgMarksEntry.Item(4, i).Value >= 65 Then
            dgMarksEntry.Item(5, i).Value = "C4"
            dgMarksEntry.Item(6, i).Value = "Credit"
        ElseIf dgMarksEntry.Item(4, i).Value >= 60 Then
            dgMarksEntry.Item(5, i).Value = "C5"
            dgMarksEntry.Item(6, i).Value = "Credit"
        ElseIf dgMarksEntry.Item(4, i).Value >= 55 Then
            dgMarksEntry.Item(5, i).Value = "C6"
            dgMarksEntry.Item(6, i).Value = "Credit"
        ElseIf dgMarksEntry.Item(4, i).Value >= 50 Then
            dgMarksEntry.Item(5, i).Value = "D7"
            dgMarksEntry.Item(6, i).Value = "Pass"
        ElseIf dgMarksEntry.Item(4, i).Value >= 40 Then
            dgMarksEntry.Item(5, i).Value = "E8"
            dgMarksEntry.Item(6, i).Value = "Weak pass"
        ElseIf dgMarksEntry.Item(4, i).Value <= 39 Then
            dgMarksEntry.Item(5, i).Value = "F9"
            dgMarksEntry.Item(6, i).Value = "Fail"
        End If
    Next

用于i=0到100
dgMarksEntry.Item（4，i）.Value=Val（dgMarksEntry.Item（3，i）.Value）+Val（dgMarksEntry.Item（2，i）.Value）
如果dgMarksEntry.Item（4，i）.Value>=80，则
dgMarksEntry.Item（5，i）.Value=“A1”
dgMarksEntry.Item（6，i）.Value=“优秀”
ElseIf dgMarksEntry.Item（4，i）.值>=75然后
dgMarksEntry.Item（5，i）.Value=“B2”
dgMarksEntry.Item（6，i）.Value=“非常好”
ElseIf dgMarksEntry.Item（4，i）.值>=70然后
dgMarksEntry.Item（5，i）.Value=“B3”
dgMarksEntry.Item（6，i）.Value=“良好”
ElseIf dgMarksEntry.Item（4，i）.值>=65然后
dgMarksEntry.Item（5，i）.Value=“C4”
dgMarksEntry.Item（6，i）.Value=“信用”
ElseIf dgMarksEntry.Item（4，i）.值>=60然后
dgMarksEntry.第（5，i）项.Value=“C5”
dgMarksEntry.Item（6，i）.Value=“信用”
ElseIf dgMarksEntry.Item（4，i）.值>=55然后
dgMarksEntry.Item（5，i）.Value=“C6”
dgMarksEntry.Item（6，i）.Value=“信用”
ElseIf dgMarksEntry.项（4，i）.值>=50，则
dgMarksEntry.Item（5，i）.Value=“D7”
dgMarksEntry.Item（6，i）.Value=“通过”
ElseIf dgMarksEntry.Item（4，i）.值>=40然后
dgMarksEntry.Item（5，i）.Value=“E8”
dgMarksEntry.Item（6，i）.Value=“弱通过”
ElseIf dgMarksEntry.Item（4，i）.Value您需要做的所有事情都在这一页上，包括一些开始的示例

我会选择一种完全不同的方法。首先，声明一个类，该类可以包含评级信息：

Public Class CreditRating
    Private m_Limit As Integer
    Public Property Limit() As Integer
        Get
            Return m_Limit
        End Get
        Set(ByVal value As Integer)
            m_Limit = value
        End Set
    End Property

    Private m_Rating As String
    Public Property Rating() As String
        Get
            Return m_Rating
        End Get
        Set(ByVal value As String)
            m_Rating = value
        End Set
    End Property

    Private m_Appreciation As String
    Public Property Appreciation() As String
        Get
            Return m_Appreciation
        End Get
        Set(ByVal value As String)
            m_Appreciation = value
        End Set
    End Property
End Class

然后将逻辑更改为：

Dim ratings As New List(Of CreditRating)

ratings.Add(New CreditRating With {.Limit = 80, .Rating = "A1", .Appreciation = "Excellent"})
ratings.Add(New CreditRating With {.Limit = 75, .Rating = "B2", .Appreciation = "Very good"})
ratings.Add(New CreditRating With {.Limit = 70, .Rating = "B3", .Appreciation = "Good"})
ratings.Add(New CreditRating With {.Limit = 65, .Rating = "C4", .Appreciation = "Credit"})
ratings.Add(New CreditRating With {.Limit = 60, .Rating = "C5", .Appreciation = "Credit"})
ratings.Add(New CreditRating With {.Limit = 55, .Rating = "C6", .Appreciation = "Credit"})
ratings.Add(New CreditRating With {.Limit = 50, .Rating = "D7", .Appreciation = "Pass"})
ratings.Add(New CreditRating With {.Limit = 40, .Rating = "E8", .Appreciation = "Weak pass"})
ratings.Add(New CreditRating With {.Limit = 0, .Rating = "F9", .Appreciation = "Fail"})

For i As Integer = 0 To 100
    Dim value As Double = Conversion.Val(dgMarksEntry(3, i).Value) + Conversion.Val(dgMarksEntry(2, i).Value)
    dgMarksEntry(4, i).Value = value
    For Each rating As CreditRating In ratings
        If value >= rating.Limit Then
            dgMarksEntry(5, i).Value = rating.Rating
            dgMarksEntry(6, i).Value = rating.Appreciation
            Exit For
        End If
    Next
Next

通过这种方法，您还可以从文件或数据库中读取评级信息。这使得更改限制更容易。它也不太容易出错，因为逻辑只编程一次，所有限制都是相同的。
您想让我们为您编码吗？？！请显示您的SQL。。。你试过什么？什么不起作用？我已经检查了链接，但我仍然可以得到它非常好。请尝试更改我的IF-ELSE语句以为我选择案例。请给我举个例子。@Akaglo:如果dgMarksEntry.Item（4，i）.Value>=80，那么您是否尝试编写了
案例dgMarksEntry.Item（4，i）.Value>=80？等等…非常感谢。我完全理解你的代码。它工作得很好。