Sub / Function array parameter altered

Question

I have a Sub with an array of strings as parameter:

Private Sub des(ByVal array() As String)

    Dim i As Integer

    For i = 0 To UBound(array)
        array(         


        

Answer 1

In Visual Basic .NET, regarding arrays as parameters, there are two important rules you have to be aware of:

Arrays themselves can be passed as ByVal and ByRef.

Arrays' elements can always be modified from the function or subroutine.

You already know that you can modify the elements of an array inside a subprocess (subroutine or function), no matter how that array is defined as parameter inside that subprocess.

So, given these two subroutines:

Private Sub desval(ByVal array() As String)
    array = {}
End Sub

Private Sub desref(ByRef array() As String)
    array = {}
End Sub

And this very simple auxiliary subroutine (here I'll use the Console):

Private Sub printArr(ByVal array() As String)
    For Each str In array
        Console.WriteLine(str)
    Next
End Sub

you can do these simple tests:

Dim arr1() as String = {"abc", "xyz", "asdf"}

Console.WriteLine("Original array:")
printArr(arr1)
Console.WriteLine()
Console.WriteLine("After desval:")
desval(arr1)
printArr(arr1)
Console.WriteLine()
Console.WriteLine("After desref:")
desref(arr1)
printArr(arr1)