创建作为参数给定的类型的新实例

Question

我已经搜索了一个答案并找到了一些c#-examples,但无法在vb.net中运行:

我想到了类似以下内容:

public function f(ByVal t as System.Type)
  dim obj as t
  dim a(2) as t

  obj = new t
  obj.someProperty = 1
  a(0) = obj

  obj = new t
  obj.someProperty = 2
  a(1) = obj

  return a
End Function

我知道,我可以使用Activator.Create ...方法创建一个新实例,但是如何创建这种类型的数组或者只是声明一个新变量？(暗淡)

提前致谢!

Answer 1

Personaly我更喜欢这种语法.

Public Class Test(Of T As {New})
    Public Shared Function GetInstance() As T
        Return New T
    End Function
End Class

或者,如果您想限制可能的类型:

Public Class Test(Of T As {New, MyObjectBase})
    Public Shared Function GetInstance() As T
        Return New T
    End Function
End Class

Answer 2

这实际上取决于类型本身.如果类型是引用类型并且具有空构造函数(接受零参数的构造函数),则以下代码应创建它的一个内容:使用泛型:

Public Function f(Of T)() As T
    Dim tmp As T = GetType(T).GetConstructor(New System.Type() {}).Invoke(New Object() {})
    Return tmp
End Function

使用类型参数:

Public Function f(ByVal t As System.Type) As Object
    Return t.GetConstructor(New System.Type() {}).Invoke(New Object() {})
End Function