How to update RefersToR1C1 Excel named range in Visual Studio/VB - excel

Question

Latest edit: I've tried a ton of stuff, still can't figure this out. A more concise question is how I assign the variable. Per the first comment I got, I'm using VSTO.
Dim wksSheetVSTO As Worksheet = Globals.Factory.GetVstoObject(wsThisSheet)
Dim nrThisNamedRange As NamedRange = ???
Original Question:
I am brand new to Visual Studio/VB.Net but am an experienced VBA programmer. I have a very complex spreadsheet that uses Excel named ranges, and I can’t seem to figure out how I can manipulate them.
The existing spreadsheet uses Excel named ranges that essentially act like database tables. When a user adds a row, it adds a row to the named range. Since Excel doesn’t automatically extend the range itself, the VBA code re-defines the named range to include the new row by re-defining the RefersToR1C1 property of the named range. It works perfectly in VBA. (I can post the working VBA code if it helps.)
In Visual Studio/VB, I can’t figure out a way to assign a variable to the named range. The only documentation I can find talks about assigning a variable by creating a NEW named range, but I already have the named range. My work-around (which works, but looks bad to me) is below:
Dim rngDataStore As Excel.Range
Dim nrThisNamedRange As NamedRange
...<<stuff happening here>>...
rngDataStore.Resize(1).Insert(Excel.XlInsertShiftDirection.xlShiftDown)
' The next line is what I don't want.
nrThisNamedRange = wksSheetVSTO.Controls.AddNamedRange(wksSheetVSTO.Range("A1"), <<name>>)
nrThisNamedRange.RefersToR1C1 = <<new named range R1C1 here>>
I don’t want to just extend the working range (rngDataStore), I need to actually update the definition of the named range so that I can continue to reference and write to it. (This is doing what ctrl+F3 allows you to do within Excel.) I’ve tried looping through the Names collection, but other than using the ‘Controls.AddNamedRange’ I can’t figure out how to simply assign the nrThisNamedRange variable and update its RefersToR1C1 property.
Added: The above code doesn't always work, it's giving me an error that the named range already exists. (Which of course I know!)

Answer 1

For global named range:
Dim name = Globals.ThisWorkbook.Names.Item("name")
Dim range = name.RefersToRange
name.RefersTo = range.Resize(range.Rows.Count + 1)

Answer 2

#Slai helped me uncover the answer (the worksheet had global named ranges in it) so I thought I'd at least share the full function for anyone who might need it.
Function ExpandNamedRange(sRangeName As String, lRowsToAdd As Long, sSheetName As String) As Boolean
' Adds the specified number of rows and resets the surrounding named range.
Dim wsThisSheet As Excel.Worksheet = Globals.ThisWorkbook.Application.Worksheets(sSheetName)
Dim rngDataStore As Excel.Range = wsThisSheet.Range(sRangeName)
If lRowsToAdd > 0 Then
rngDataStore.Resize(lRowsToAdd).Insert(Excel.XlInsertShiftDirection.xlShiftDown)
' For a global/workbook named range
Globals.ThisWorkbook.Names.Item(sRangeName).RefersToR1C1 = "=" & wsThisSheet.Name &
"!R" & rngDataStore.Row - lRowsToAdd & "C" & rngDataStore.Column &
":R" & rngDataStore.Row + rngDataStore.Rows.Count - 1 & "C" & rngDataStore.Column + rngDataStore.Columns.Count - 1
' For a local/worksheet named range
'wsThisSheet.Names.Item(sRangeName).RefersToR1C1 = "=" & wsThisSheet.Name &
' "!R" & rngDataStore.Row - lRowsToAdd & "C" & rngDataStore.Column &
' ":R" & rngDataStore.Row + rngDataStore.Rows.Count - 1 & "C" & rngDataStore.Column + rngDataStore.Columns.Count - 1
End If
Return True
End Function
Two things I learned:
(1) I didn't actually have to refer to a NamedRange object at all, I could just use the Names collection of the workbook; I was originally trying that because my first attempts failed. But this is nice, it saved me steps.
(2) In VBA, you can refer to 'global' Named Ranges from anywhere. That's where I got stuck.