Vb.net 对象引用未设置为对象的实例。visualbasicvb

java中的相同代码在

我用VB已经有一段时间了，但我认为

New

-方法中的

DIM

-语句创建了一个新的局部变量

tours

，它隐藏了全局变量

tours

试试这个：

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

---

我已经用VB做了一段时间了，但是我认为

New

-方法中的

DIM

-语句创建了一个新的局部变量

tours

，它隐藏了全局变量

tours

试试这个：

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

试试看

试试看

---

请注意，数组的大小将为populationSize+1，因为在VB中，数组声明中传递的值是上限，而不是大小。请注意，数组的大小将为populationSize+1，因为在VB中，数组声明中传递的值是上限，而不是大小。

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