Edit Value In Excel Range - vb.net

Question

I have an excel sheet with values in a range which I want to perform some calculations on in vb.net. I pass that range to vb.net using COM. When I try editing the values of the range, nothing happens.
My question seems to be very similar to these questions, but I can't quite figure out what step I am missing.
How to edit cell value in VB.net - Using .Interop.Excel
VB.net Office Solution - Accessing value in named Range in a Worksheet
VBA CODE:
Function MyTestRange (Byref myrng as range)
Set classLib = New VBProject.CClass
MyTestRange = classLib.MyTestRange(myrng)
End Function
VB.NET code
Imports Microsoft.Office.Interop.Excel
Public Class CClass
Function MyTestRange(ByRef myrng As Range) As Double
Dim newrng As Range
Dim b As Integer = myrng.Rows.Count
Dim i As Integer
newrng = myrng
For i = 1 To b
newrng.Value2(i, 1) = myrng.Value2(i, 1) + 1
Next i
MyTestRange = newrng.Value2(1, 1)
End Function
End class
While this code doesn't generate an error, it doesn't change the values in newrng.
Edit:
I have tried many iterations based on the link provide, but always get the same error :
An exception of type 'System.Runtime.InteropServices.COMException' occurred in mscorlib.dll but was not handled in user code
Additional information: Exception from HRESULT: 0x800A03EC
This is the simplest way to generate the error:
Dim c As Object
c = myrng.Value
myrng.Value = c
Hence amending the values to something new, seems out of reach!
Edit 2:
After chatting with user Mat's Mug, I tried to edit a value in a range, purely in VBA.
This sub works perfectly:
Sub rangesub()
Dim example As Range
Set example = Range("A1:A4")
example.Value = Application.Transpose(Array(1, 2, 3, 4))
End Sub
Excel functions also seem able to handle passing ranges:
Function SimpleCopyRange(myrng)
SimpleCopyRange = myrng
End Function
A very simple combination of this code works:
Function EditRange(myrng)
Dim example As Range
Set example = Range("A1:A4")
EditRange = example
End Function
However there is an unspecified error if I try to edit the range:
Function EditRange(myrng)
Dim example As Range
Set example = Range("A1:A4")
example.Value = Application.Transpose(Array(1, 2, 3, 4))
EditRange = example
End Function
The application.transpose part obviously adds a layer of complexity, and can be replaced with example.Value = 8 without any changes in results.

Answer 1

Looking at this question/answer:
Excel VBA: Iterating over range parameter and change cell values
It appears that a UDF can only change the calling cell.
I think therefore this method is impossible.
The workaround is to to rewrite the code to work with an array, assign the range to an array, edit the array and pass it to the new function.