Excel VBA reference to other workbook through "set" with generic variables, keeping that reference in formulas - vba

Question

Here's my problem. I'm running a central KPI file that has to be updated each week. It is refering to files that have a specific name + the current week that they're in. For example, the KPI refers to a DT1P and MPO file, both ending with the current week.
So, for week 2016-28, the central KPI file should look up the values in MPO2016-28.xlsx and DT1P2016-28.xlsx.
For week 2016-29, the central KPI file should look up the values in MPO2016-29.xlsx and DT1P2016-29.xlsx.
However, when I try to run formulas to do some calculations from those sheets, I have no clue how I can make the week generic (the week is being made in Range("E1") in the KPI file), without just refering to the entire location the file is. How can I solve this?
I have:
Set wb_MPO = Workbooks.Open("\\S007v\MPO" & Range("e1").Value & ".xlsx")
wb_KPI.Activate
Set wb_DT1P = Workbooks.Open("\\S007v\DT1P" & Range("e1").Value & ".xlsx")
wb_KPI.Activate
To define the files that need to be opened.
However, my formulas look like this (there's many more of them, but the principle stays the same, so I won't bother you with them)
Range("E4").FormulaR1C1 = _
"=INDEX('[MPO2016-28.xlsx]CSR MPO'!C10,MATCH(RC[-4],'[MPO2016-28.xlsx]CSR MPO'!C1,0),0)"
Could it be something like:
Range("E4").FormulaR1C1 = _
"=INDEX('[wb_MPO]CSR MPO'!C10,MATCH(RC[-4],'[wb_MPO]CSR MPO'!C1,0),0)"
Or am I totally off?
Thanks in advance for your support :)

Answer 1

You have the right idea, but it would be:
Range("E4").FormulaR1C1 = _
"=INDEX('[" & wb_MPO.Name & "]CSR MPO'!C10,MATCH(RC[-4],'[" & wb_MPO.Name & "]CSR MPO'!C1,0),0)"
This will only work if the workbook you are trying to reference is open though. I feel like there are probably better ways to extract this information than opening the workbook and writing a formula to a cell.