初始化集合类
问题描述:
是否有办法让类继承类的集合被初始化?初始化集合类
例如,这里是我的代码:
Public Class CamryCar
Property Name As String = "Camry"
Property Color As String
End Class
Public Class RedCamry
Inherits CamryCar
Sub New()
MyBase.New()
Color = "Red"
End Sub
End Class
Public Class BlueCamry
Inherits CamryCar
Sub New()
MyBase.New()
Color = "Blue"
End Sub
End Class
我在做什么今天的colllection是:
Public Class Camrys
Property Cars As New List(Of CamryCar) From {New RedCamry, New BlueCamry}
End Class
但是这给了我的Cars
额外的属性。
我也可以这样做:
Public Class Camrys
Inherits List(Of CamryCar)
End Class
我喜欢这个,因为我没有额外的属性来处理。但我可以通过RedCamry
和BlueCamry
的对象找到一种方法来初始化该列表。
难道还有其他方法可以做到吗?
答
只是另一种选择。我可能会将该列表传递给构造函数。我还添加了一个额外的Sub New(),它将通过反射初始化集合。
Imports System.Reflection
Module Module1
Sub Main()
Dim camrys As New Camrys
For Each camry As CamryCar In camrys
Console.WriteLine(camry.Color)
Next
Console.ReadKey()
End Sub
End Module
Public Class Car
End Class
Public Class CamryCar
Inherits Car
Property Name As String = "Camry"
Property Color As String
End Class
Public Class RedCamry
Inherits CamryCar
Sub New()
MyBase.New()
Color = "Red"
End Sub
End Class
Public Class BlueCamry
Inherits CamryCar
Sub New()
MyBase.New()
Color = "Blue"
End Sub
End Class
Public Class Camrys
Inherits List(Of CamryCar)
Public Sub New(ByVal Camrys As List(Of CamryCar))
MyBase.New()
For Each Camry As CamryCar In Camrys
Add(Camry)
Next
End Sub
Public Sub New()
MyBase.New()
InitializeCamrys()
End Sub
Public Sub InitializeCamrys()
Dim asm As Assembly = Assembly.GetExecutingAssembly()
For Each t As Type In asm.GetTypes()
If GetType(CamryCar) Is t.BaseType Then
Dim camry As CamryCar = Activator.CreateInstance(t)
Add(camry)
End If
Next
End Sub
End Class
答
看起来你正在寻找工厂风格的功能。现在
Module Factory
Public Function CreateCamrysList As List(of CamryCar)
Return New List(Of CamryCar) From {New RedCamry, New BlueCamry}
End Function
End Module
只要您需要CamryCar
对象列表,你可以使用函数CreateCamrysList
。
注:从List(Of T)
导出通常是一个不好的解决方案。如果你确实需要推导出更好的选择Collection(Of T)
。
+2
出于好奇,为什么从List(Of T)得出一个不好的解决方案? – Stan 2010-10-05 04:21:27
答
你需要在构造函数初始化:
Public Class Camrys
Inherits List(Of CamryCar)
Public Sub New()
MyBase.New()
Add(New RedCamry())
Add(New BlueCamry())
End Sub
End Class
+1用于使用反射自动添加所有版本的CamryCar。 – awe 2010-10-20 08:13:52
谢谢。我认为这很聪明。 :) – 2010-10-20 14:21:31
辉煌!谢谢。 – Stan 2010-10-20 17:15:36