why*_*heq 5 vb.net enums design-patterns
目前我有我的底层模型的代码:
Public Enum vehicleType
Car
Lorry
Bicycle
End Enum
Public Class TrafficSurveyA
' Declare the fields here.
Private fCars As Integer
Private fBicycles As Integer
Private fLorries As Integer
Public Sub New()
' An instance of TrafficSurveyA is created with all vehicle counts set to zero.
fCars = 0
fBicycles = 0
fLorries = 0
End Sub
Public Sub incrementCount(ByVal vehicle As vehicleType)
' Preconditions: none
' Postconditions: If vehicle is "Car", "Bicycle" or "Lorry" then 1 is added
' to the corresponding count. Otherwise nothing is done.
Select Case vehicle
Case vehicleType.Car : fCars = fCars + 1
Case vehicleType.Bicycle : fBicycles = fBicycles + 1
Case vehicleType.Lorry : fLorries = fLorries + 1
Case Else 'do nothing
End Select
End Sub
Public Function getCount(ByVal vehicle As vehicleType) As String
' Preconditions: none
' Postconditions: If vehicle is "Car", "Bicycle" or "Lorry", the string
' representation of the corresponding count is returned.
' Otherwise the empty string is returned.
Dim result As String
result = ""
Select Case vehicle
Case vehicleType.Car : result = Convert.ToString(fCars)
Case vehicleType.Bicycle : result = Convert.ToString(fBicycles)
Case vehicleType.Lorry : result = Convert.ToString(fLorries)
Case Else : result = ""
End Select
Return result
End Function
Public ReadOnly Property Vehicles() As String
' Preconditions: none
' Postconditions: The total number of vehicles recorded is returned.
Get
Return (fCars + fBicycles + fLorries).ToString()
End Get
End Property
End Class
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似乎Enum可以很容易地放在TrafficSurveyA类中,就像这样......
Public Class TrafficSurveyA
Enum vehicleType
Car
Lorry
Bicycle
End Enum
' Declare the fields here.
Private fCars As Integer
Private fBicycles As Integer
Private fLorries As Integer
Public Sub New()
' An instance of TrafficSurveyA is created with all vehicle counts set to zero.
fCars = 0
fBicycles = 0
fLorries = 0
End Sub
...
...
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唯一的区别似乎是我需要使用的GUI代码TrafficSurveyA.vehicleType.Lorry而不是这个vehicleType.Lorry.
两者似乎都运行正常,但枚举类型的这些实现之一是错误的吗?