Asp.net 减少VB.NET中if代码的数量_Asp.net_Vb.net_Web

Asp.net 减少VB.NET中if代码的数量

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Asp.net 减少VB.NET中if代码的数量,asp.net,vb.net,web,Asp.net,Vb.net,Web,我正在使用ASP Web窗体和VB后端创建一个太阳能光伏计算器。我只是看看我的代码，作为一名VB.NET开发新手，我只是想知道是否有一种方法可以做一些不同的事情，减少代码行数或类似的事情。下面是y代码中一个麻烦的部分： Dim SR As Integer 'Store radiation value If drpDwnRoofFacing.Text = "South" And drpAngleOfRoof.Text = "Horizontal" Then SR =

我正在使用ASP Web窗体和VB后端创建一个太阳能光伏计算器。我只是看看我的代码，作为一名VB.NET开发新手，我只是想知道是否有一种方法可以做一些不同的事情，减少代码行数或类似的事情。下面是y代码中一个麻烦的部分：

Dim SR As Integer
    'Store radiation value
    If drpDwnRoofFacing.Text = "South" And drpAngleOfRoof.Text = "Horizontal" Then
        SR = 933
    ElseIf drpDwnRoofFacing.Text = "SE/SW" And drpAngleOfRoof.Text = "Horizontal" Then
        SR = 933
    ElseIf drpDwnRoofFacing.Text = "E/W" And drpAngleOfRoof.Text = "Horizontal" Then
        SR = 933
    ElseIf drpDwnRoofFacing.Text = "NE/NW" And drpAngleOfRoof.Text = "Horizontal" Then
        SR = 933
    ElseIf drpDwnRoofFacing.Text = "North" And drpAngleOfRoof.Text = "Horizontal" Then
        SR = 933
    ElseIf drpDwnRoofFacing.Text = "South" And drpAngleOfRoof.Text = "30 Degrees" Then
        SR = 1042
    ElseIf drpDwnRoofFacing.Text = "SE/SW" And drpAngleOfRoof.Text = "30 Degrees" Then
        SR = 997
    ElseIf drpDwnRoofFacing.Text = "E/W" And drpAngleOfRoof.Text = "30 Degrees" Then
        SR = 886
    ElseIf drpDwnRoofFacing.Text = "NE/NW" And drpAngleOfRoof.Text = "30 Degrees" Then
        SR = 762
    ElseIf drpDwnRoofFacing.Text = "North" And drpAngleOfRoof.Text = "30 Degrees" Then
        SR = 709
    ElseIf drpDwnRoofFacing.Text = "South" And drpAngleOfRoof.Text = "45 Degrees" Then
        SR = 1023
    ElseIf drpDwnRoofFacing.Text = "SE/SW" And drpAngleOfRoof.Text = "45 Degrees" Then
        SR = 968
    ElseIf drpDwnRoofFacing.Text = "E/W" And drpAngleOfRoof.Text = "45 Degrees" Then
        SR = 829
    ElseIf drpDwnRoofFacing.Text = "NE/NW" And drpAngleOfRoof.Text = "45 Degrees" Then
        SR = 666
    ElseIf drpDwnRoofFacing.Text = "North" And drpAngleOfRoof.Text = "45 Degrees" Then
        SR = 621
    ElseIf drpDwnRoofFacing.Text = "South" And drpAngleOfRoof.Text = "60 Degrees" Then
        SR = 960
    ElseIf drpDwnRoofFacing.Text = "SE/SW" And drpAngleOfRoof.Text = "60 Degrees" Then
        SR = 900
    ElseIf drpDwnRoofFacing.Text = "E/W" And drpAngleOfRoof.Text = "60 Degrees" Then
        SR = 753
    ElseIf drpDwnRoofFacing.Text = "NE/NW" And drpAngleOfRoof.Text = "60 Degrees" Then
        SR = 580
    ElseIf drpDwnRoofFacing.Text = "North" And drpAngleOfRoof.Text = "60 Degrees" Then
        SR = 485
    ElseIf drpDwnRoofFacing.Text = "South" And drpAngleOfRoof.Text = "Vertical" Then
        SR = 724
    ElseIf drpDwnRoofFacing.Text = "SE/SW" And drpAngleOfRoof.Text = "Vertical" Then
        SR = 684
    ElseIf drpDwnRoofFacing.Text = "E/W" And drpAngleOfRoof.Text = "Vertical" Then
        SR = 565
    ElseIf drpDwnRoofFacing.Text = "NE/NW" And drpAngleOfRoof.Text = "Vertical" Then
        SR = 427
    ElseIf drpDwnRoofFacing.Text = "North" And drpAngleOfRoof.Text = "Vertical" Then
        SR = 360
    End If

您可以嵌套IF语句，即


如果drpAngleOfRoof.Text=“水平”，则
如果结束

例如，将与每个角度位置相关的所有语句组合在一起

或者您可以使用Select…Case语句作为替代

我建议将这些数据存储在应用程序代码之外，例如存储在数据库中，或者如果不需要，存储在XML文件中。但是，即使要在代码中硬编码转换规则，最好还是将规则的硬编码与处理和应用规则的逻辑分开。例如，您可以创建一个包含规则的类，如下所示：

Public Class MyRule
    Public Sub New(roofFacing As String, angleOfRoof As String, SR As Integer)
        _roofFacing = roofFacing
        _angleOfRoof = angleOfRoof
        _SR = sr
    End New

    Public ReadOnly Property RoofFacing() As String
        Get
            Return _roofFacing
        End Get
    End Property
    Private _roofFacing As String

    Public ReadOnly Property AngleOfRoof() As String
        Get
            Return _angleOfRoof
        End Get
    End Property
    Private _angleOfRoofAs String

    Public ReadOnly Property SR() As String
        Get
            Return _SR
        End Get
    End Property
    Private _SR String
End Class

Dim rules As New List(Of MyRule)()
rules.Add(New MyRule("South", "Horizontal", 933))
rules.Add(New MyRule("South", "SE/SW", 933))
' ...
rules.Add(New MyRule("South", Nothing, 933))

Dim SR As Integer
For Each rule As MyRule In rules
    If _
    ( _
        (rule.RoofFacing Is Nothing) OrEsle _
        (rule.RoofFacing = drpDwnRoofFacing.Text) _
    ) AndAlso _
    ( _
        (rule.AngleOfRoof Is Nothing) OrEsle _
        (rule.AngleOfRoof = drpAngleOfRoof.Text) _
    ) Then
        SR = rule.SR
        Exit For
    End If
Next

Select Case drpAngleOfRoof.Text
Case "Horizontal"
    Return 933
Case "30 Degrees"
    Select Case drpDwnRoofFacing.Text
        Case "South"
            Return 1042
        Case "SE/SW"
            Return 997
        Case "E/W"
            Return 886
        Case "NE/NW"
            Return 762
        Case "North"
            Return 709
    End Select
Case "45 Degrees"
    Select Case drpDwnRoofFacing.Text
        Case "South"
            Return 1023
        Case "SE/SW"
            Return 968
        Case "E/W"
            Return 829
        Case "NE/NW"
            Return 666
        Case "North"
            Return 621
    End Select
Case "60 Degrees"
    Select Case drpDwnRoofFacing.Text
        Case "South"
            Return 960
        Case "SE/SW"
            Return 900
        Case "E/W"
            Return 753
        Case "NE/NW"
            Return 580
        Case "North"
            Return 485
    End Select
Case "Vertical"
    Select Case drpDwnRoofFacing.Text
        Case "South"
            Return 724
        Case "SE/SW"
            Return 684
        Case "E/W"
            Return 565
        Case "NE/NW"
            Return 427
        Case "North"
            Return 360
    End Select
End Select

然后，您可以硬编码规则列表的创建，就像它们来自数据库一样，如下所示：

Public Class MyRule
    Public Sub New(roofFacing As String, angleOfRoof As String, SR As Integer)
        _roofFacing = roofFacing
        _angleOfRoof = angleOfRoof
        _SR = sr
    End New

    Public ReadOnly Property RoofFacing() As String
        Get
            Return _roofFacing
        End Get
    End Property
    Private _roofFacing As String

    Public ReadOnly Property AngleOfRoof() As String
        Get
            Return _angleOfRoof
        End Get
    End Property
    Private _angleOfRoofAs String

    Public ReadOnly Property SR() As String
        Get
            Return _SR
        End Get
    End Property
    Private _SR String
End Class

Dim rules As New List(Of MyRule)()
rules.Add(New MyRule("South", "Horizontal", 933))
rules.Add(New MyRule("South", "SE/SW", 933))
' ...
rules.Add(New MyRule("South", Nothing, 933))

Dim SR As Integer
For Each rule As MyRule In rules
    If _
    ( _
        (rule.RoofFacing Is Nothing) OrEsle _
        (rule.RoofFacing = drpDwnRoofFacing.Text) _
    ) AndAlso _
    ( _
        (rule.AngleOfRoof Is Nothing) OrEsle _
        (rule.AngleOfRoof = drpAngleOfRoof.Text) _
    ) Then
        SR = rule.SR
        Exit For
    End If
Next

Select Case drpAngleOfRoof.Text
Case "Horizontal"
    Return 933
Case "30 Degrees"
    Select Case drpDwnRoofFacing.Text
        Case "South"
            Return 1042
        Case "SE/SW"
            Return 997
        Case "E/W"
            Return 886
        Case "NE/NW"
            Return 762
        Case "North"
            Return 709
    End Select
Case "45 Degrees"
    Select Case drpDwnRoofFacing.Text
        Case "South"
            Return 1023
        Case "SE/SW"
            Return 968
        Case "E/W"
            Return 829
        Case "NE/NW"
            Return 666
        Case "North"
            Return 621
    End Select
Case "60 Degrees"
    Select Case drpDwnRoofFacing.Text
        Case "South"
            Return 960
        Case "SE/SW"
            Return 900
        Case "E/W"
            Return 753
        Case "NE/NW"
            Return 580
        Case "North"
            Return 485
    End Select
Case "Vertical"
    Select Case drpDwnRoofFacing.Text
        Case "South"
            Return 724
        Case "SE/SW"
            Return 684
        Case "E/W"
            Return 565
        Case "NE/NW"
            Return 427
        Case "North"
            Return 360
    End Select
End Select

然后，您可以使用一个简单的循环来应用规则，而不是一个巨大的

If

语句，如下所示：

Public Class MyRule
    Public Sub New(roofFacing As String, angleOfRoof As String, SR As Integer)
        _roofFacing = roofFacing
        _angleOfRoof = angleOfRoof
        _SR = sr
    End New

    Public ReadOnly Property RoofFacing() As String
        Get
            Return _roofFacing
        End Get
    End Property
    Private _roofFacing As String

    Public ReadOnly Property AngleOfRoof() As String
        Get
            Return _angleOfRoof
        End Get
    End Property
    Private _angleOfRoofAs String

    Public ReadOnly Property SR() As String
        Get
            Return _SR
        End Get
    End Property
    Private _SR String
End Class

Dim rules As New List(Of MyRule)()
rules.Add(New MyRule("South", "Horizontal", 933))
rules.Add(New MyRule("South", "SE/SW", 933))
' ...
rules.Add(New MyRule("South", Nothing, 933))

Dim SR As Integer
For Each rule As MyRule In rules
    If _
    ( _
        (rule.RoofFacing Is Nothing) OrEsle _
        (rule.RoofFacing = drpDwnRoofFacing.Text) _
    ) AndAlso _
    ( _
        (rule.AngleOfRoof Is Nothing) OrEsle _
        (rule.AngleOfRoof = drpAngleOfRoof.Text) _
    ) Then
        SR = rule.SR
        Exit For
    End If
Next

Select Case drpAngleOfRoof.Text
Case "Horizontal"
    Return 933
Case "30 Degrees"
    Select Case drpDwnRoofFacing.Text
        Case "South"
            Return 1042
        Case "SE/SW"
            Return 997
        Case "E/W"
            Return 886
        Case "NE/NW"
            Return 762
        Case "North"
            Return 709
    End Select
Case "45 Degrees"
    Select Case drpDwnRoofFacing.Text
        Case "South"
            Return 1023
        Case "SE/SW"
            Return 968
        Case "E/W"
            Return 829
        Case "NE/NW"
            Return 666
        Case "North"
            Return 621
    End Select
Case "60 Degrees"
    Select Case drpDwnRoofFacing.Text
        Case "South"
            Return 960
        Case "SE/SW"
            Return 900
        Case "E/W"
            Return 753
        Case "NE/NW"
            Return 580
        Case "North"
            Return 485
    End Select
Case "Vertical"
    Select Case drpDwnRoofFacing.Text
        Case "South"
            Return 724
        Case "SE/SW"
            Return 684
        Case "E/W"
            Return 565
        Case "NE/NW"
            Return 427
        Case "North"
            Return 360
    End Select
End Select

正如您所看到的，一旦您以这种方式进行设计，以后修改规则或添加其他规则将更加容易。但是，您应该对这些值使用枚举，而不是字符串。例如：

Public Enum RoofFacings
    Any
    North
    South
    EastOrWest
    ' ...
End Enum

Public Enum AnglesOfRoof
    Any
    Horizontal
    Degrees30
    Degrees45
    ' ...
    Vertical
End Enum

改用select语句怎么样。您将把最初的选择削减到drpAngleOfRoof的值，然后只需要担心drpdownroof的值。大概是这样的：

Public Class MyRule
    Public Sub New(roofFacing As String, angleOfRoof As String, SR As Integer)
        _roofFacing = roofFacing
        _angleOfRoof = angleOfRoof
        _SR = sr
    End New

    Public ReadOnly Property RoofFacing() As String
        Get
            Return _roofFacing
        End Get
    End Property
    Private _roofFacing As String

    Public ReadOnly Property AngleOfRoof() As String
        Get
            Return _angleOfRoof
        End Get
    End Property
    Private _angleOfRoofAs String

    Public ReadOnly Property SR() As String
        Get
            Return _SR
        End Get
    End Property
    Private _SR String
End Class

Dim rules As New List(Of MyRule)()
rules.Add(New MyRule("South", "Horizontal", 933))
rules.Add(New MyRule("South", "SE/SW", 933))
' ...
rules.Add(New MyRule("South", Nothing, 933))

Dim SR As Integer
For Each rule As MyRule In rules
    If _
    ( _
        (rule.RoofFacing Is Nothing) OrEsle _
        (rule.RoofFacing = drpDwnRoofFacing.Text) _
    ) AndAlso _
    ( _
        (rule.AngleOfRoof Is Nothing) OrEsle _
        (rule.AngleOfRoof = drpAngleOfRoof.Text) _
    ) Then
        SR = rule.SR
        Exit For
    End If
Next

Select Case drpAngleOfRoof.Text
Case "Horizontal"
    Return 933
Case "30 Degrees"
    Select Case drpDwnRoofFacing.Text
        Case "South"
            Return 1042
        Case "SE/SW"
            Return 997
        Case "E/W"
            Return 886
        Case "NE/NW"
            Return 762
        Case "North"
            Return 709
    End Select
Case "45 Degrees"
    Select Case drpDwnRoofFacing.Text
        Case "South"
            Return 1023
        Case "SE/SW"
            Return 968
        Case "E/W"
            Return 829
        Case "NE/NW"
            Return 666
        Case "North"
            Return 621
    End Select
Case "60 Degrees"
    Select Case drpDwnRoofFacing.Text
        Case "South"
            Return 960
        Case "SE/SW"
            Return 900
        Case "E/W"
            Return 753
        Case "NE/NW"
            Return 580
        Case "North"
            Return 485
    End Select
Case "Vertical"
    Select Case drpDwnRoofFacing.Text
        Case "South"
            Return 724
        Case "SE/SW"
            Return 684
        Case "E/W"
            Return 565
        Case "NE/NW"
            Return 427
        Case "North"
            Return 360
    End Select
End Select

更好的方法是使用

Select Case

。非常感谢，当然！选择案例，与if相比有什么好处？哇，太棒了，我喜欢你们的知识。我真的很感激。我觉得通过问这个问题，我学到了比无数个小时搜索MSDN阅读和学习每个部分更多的东西。