未将对象引用设置为对象的实例。 Visual Basic中的VB

Public Class Population 

Dim tours() As Tour ' Tour is a class and I have to make and object array 

Public Sub New(ByVal populationSize As Integer, ByVal initialise As Boolean) 

    Dim tours As New Tour(populationSize) ' 

    If initialise Then 
     ' Loop and create individuals 
     For i As Integer = 0 To (populationSize - 1) 
      Dim newTour As New Tour() 
      newTour.generateIndividual() 
      saveTour(i, newTour) 
     Next i 
    End If 
End Sub 

Public Sub saveTour(ByVal index As Integer, ByVal tour As Tour) 
    tours(index) = tour   ' getting error in this line 
End Sub

在Java

相同的代码是this link 未将对象引用设置为对象的实例。 Visual Basic中的VB

来源

2013-02-23 binit92

请注意，您的数组的大小将是族群大小+ 1，因为在VB中的数组声明传递的值是上限，不尺寸。 – 2013-02-25 16:30:48

它已经有一段时间，我已经做了VB，但我认为你语句来在New - 方法创建一个新的局部变量tours隐藏的全局变量tours。

试试这个：

Public Class Population 

Dim tours() As Tour 

Public Sub New(ByVal populationSize As Integer, ByVal initialise As Boolean) 

    tours = New Tour(populationSize) ' 

    If initialise Then 
     ' Loop and create individuals 
     For i As Integer = 0 To (populationSize - 1) 
      Dim newTour As New Tour() 
      newTour.generateIndividual() 
      saveTour(i, newTour) 
     Next i 
    End If 
End Sub 

Public Sub saveTour(ByVal index As Integer, ByVal tour As Tour) 
    tours(index) = tour 
End Sub

来源

2013-02-23 12:29:32 Koen

尝试，

Public Sub New(ByVal populationSize As Integer, ByVal initialise As Boolean) 

    ReDim tours(populationSize) 

    If initialise Then 
     ' Loop and create individuals 
     For i As Integer = 0 To (populationSize - 1) 
      Dim newTour As New Tour() 
      newTour.generateIndividual() 
      saveTour(i, newTour) 
     Next i 
    End If 
End Sub

来源

2013-02-23 12:53:47 Nalaka526

未将对象引用设置为对象的实例。 Visual Basic中的VB

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