Loop through Multiple List of objects and run a Sub

Question

Hallo,

I have multiple List of Objects for eg.

List1 As New List of (xx)
List2 As New List of (xx)
List3 As New List of (xx)
.
.
.
etc

All object has a Public sub called Reset. Which clears user entered values of the property and set the object to its default values.

I want to run this sub on all list. Currently i have a following code which works but i wanted to know if i can simplify by keeping list as variable. or any alternative way to set the list of objects to its default state?

Current code
where condition is same for all list . i just want to change the list.

List1.Where(Function(x) x......).ToList.ForEach(Sub(c) c.Reset())
List2.Where(Function(x) x......).ToList.ForEach(Sub(c) c.Reset())
List3.Where(Function(x) x......).ToList.ForEach(Sub(c) c.Reset())
.
.

Any ideas? thanks.

Answer 1

If all of the lists consist of objects of the same type (xx) and the condition is the same, then you can define a Sub:

Sub Reset(list As List(Of xx))

    For Each x In list.Where(Function ...)
        x.Reset()
    Next

End Sub

Usage:

Reset(List1)
Reset(List2)
Reset(List3)

You can also consider this:

List1.Concat(List2).Concat(List3).Where(Function ...).All(Function(x)
                                                                    x.Reset()
                                                                    Return True
                                                                End Function)

Answer 2

Hi @Hobbyist_programmer ,
You can define an extension method like:

Module ExtensionOperation  
    <Extension()>  
    Sub Reset(Of T)(ByVal lst As List(Of T), ByVal provider As Func(Of T, Boolean))  
        lst.Where(Function(x) provider(x)).ToList().ForEach(Function(c) c.GetType().GetMethod("Reset").Invoke(c, Nothing))  
    End Sub  
End Module  

Usage:

        List1.Reset(Function(x) ...)  
        List2.Reset(Function(x) ...)  

Hope it could be helpful.

Best Regards,
Xingyu Zhao
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