问为什么在lambda表达式中使用迭代变量是不好的

EN

List<Action> actions = new List<Action>();

for (int i = 0; i < 10; i++)
{
    actions.Add(() => Console.WriteLine(i));
}

foreach (Action action in actions)
{
    action();
}

' Prints 4,4,4,4
Sub VBDotNetSample()
    Dim funcList As New List(Of Func(Of Integer))

    For indexParameter As Integer = 0 To 3
        'The compiler says:
        '   Warning     BC42324 Using the iteration variable in a lambda expression may have unexpected results.  
        '   Instead, create a local variable within the loop and assign it the value of the iteration variable

        funcList.Add(Function()indexParameter)

    Next

    
    For Each lambdaFunc As Func(Of Integer) In funcList
        Console.Write($"{lambdaFunc()}")

    Next

End Sub

Module Decompiledcode
    ' Prints 4,4,4,4
    Sub CompilerGenerated()

        Dim funcList As New List(Of Func(Of Integer))
        
        '***********************************************************************************************
        ' There's only one instance of the closureHelperClass for the entire Sub
        ' That means that all the iterations of the for loop below are referencing
        ' the same class instance; that means that it can't remember the value of Local_indexParameter
        ' at each iteration, and it only remembers the last one (4).
        '***********************************************************************************************
        Dim closureHelperClass As New ClosureHelperClass_CompilerGenerated

        For closureHelperClass.Local_indexParameter = 0 To 3

            ' NOTE that it refers to the Lambda *instance* method of the ClosureHelperClass_CompilerGenerated class, 
            ' Remember that delegates implicitly carry the instance of the class in their Target 
            ' property, it's not just referring to the Lambda method, it's referring to the Lambda
            ' method on the closureHelperClass instance of the class!
            Dim closureHelperClassMethodFunc As Func(Of Integer) = AddressOf closureHelperClass.Lambda
            funcList.Add(closureHelperClassMethodFunc)
        
        Next
        'closureHelperClass.Local_indexParameter is 4 now.

        'Run each stored lambda expression (on the Delegate's Target, closureHelperClass)
        For Each lambdaFunc As Func(Of Integer) in funcList      
            
            'The return value will always be 4, because it's just returning closureHelperClass.Local_indexParameter.
            Dim retVal_AlwaysFour As Integer = lambdaFunc()

            Console.Write($"{retVal_AlwaysFour}")

        Next

    End Sub

    Friend NotInheritable Class ClosureHelperClass_CompilerGenerated
        ' Yes the compiler really does generate a class with public fields.
        Public Local_indexParameter As Integer

        'The body of your lambda expression goes here, note that this method
        'takes no parameters and uses a field of this class (the stored parameter value) instead.
        Friend Function Lambda() As Integer
            Return Me.Local_indexParameter

        End Function

    End Class

End Module