Question

我正在研究一个多线程应用程序，并遇到了在线程之间传递参数的问题。

Private Students as Students
Private ListOfStudents as List(Of Students.Student)
Public Sub AddStudents()
                Dim AddThread As New Thread(AddressOf Add)
                AddThread.SetApartmentState(ApartmentState.STA)
                AddThread.Start(Param)
End Sub

Private Sub Add(Byval Param as String)
Students = new Students(Param) 'Add Students to List
ListOfStudents = Students.GetStudents() 'Returns List of Students
For Each S in ListOfStudents
Dim L As New ListViewItem(S.Name)
        L.SubItems.Add(S.Marks)    
ListView1.Items.Add(L)    
Next
End Sub

这很好用。现在..

Public Sub GetStudentInfo()
For Each S in ListOfStudents
Dim SubThread As New Thread(AddressOf CheckStudent)
            SubThread.SetApartmentState(ApartmentState.STA)
            SubThread.IsBackground = True
            SubThread.Start(S)
Next
End Sub
Private Result as String
Private Sub CheckStudent(Byval S as Students.Student)
Result &= S.Name & ":" & S.Marks 
End Sub

结果应该是Ravi：92但它总是没有。结果为null：null / Nothing：Nothing

以下是学生班：

Public Class Students
Public Class Student
Public Property Name As String
Public Property Marks As String
End Class
Public Function GetStudents() As List(Of Student)
Dim N as New List(Of Student)
N = ''code
Return N
End Function
End Class

我做了一些研究，可能会发生这种情况，因为列表是在一个单独的线程上修改的（AddThread），而另一个线程正在调用它来检索列表（SubThread）。我该怎么办？

在线程之间传递参数/对象

0 个答案: