How to have a macro search for a value in an offset cell on one sheet in another sheet - vba

Question

this is my first question so please bear with me if i'm doing anything wrong.
Quick back storey... on sheet "Purchase" in column C i want the item name of what has been purchased, in column D i want the quantity and in column G i want the location of where the item is going. For example i want 10 boxes of tiles delivered to the office. C2=Tiles, D2=10, G2=Office
When the location of an item is entered into column G(cell change) i want the macro to offset to the same row in column C and then search for the value in column A on sheet "Office", i currently have this for searching if a cell changes;
Private Sub worksheet_change(ByVal target As Range)
Dim keycells As String
keycells = "g2:g9999"
If Application.Intersect(ActiveCell, Range(keycells)) = "Office" Then MsgBox "hello"
End Sub
This does work, but it also checks if all other cells change, which i dont want it to do this. In place of "msgbox "hello" " i want to put the script for it to offset to the same row in column C look at the value and then search for this value in column A on sheet "Office".
If it is found i need the macro to add the newly purchased quantity to the current quantity on sheet "Office" (this will be column B), if it is not found i need it add the information from columns C & D on sheet "Purchase" to columns A & B
Also i will need to add more locations to the script and will give these locations a sheet in the workbook over time
If this is possible i will be extremely gratefull for all help provided

Answer 1

The Worksheet_Change event fires on all cell changes.
To prevent your code running unless the cell is in column G, you could restrict it like this:
Private Sub worksheet_change(ByVal target As Range)
Dim keycells As String
Dim iSect
If target.Column = 7 Then
keycells = "g2:g9999"
Set iSect = Application.Intersect(target, Range(keycells))
If Not iSect Is Nothing Then
If lcase(target) = "office" Then
MsgBox "hello"
' add code here to copy the data
End If
End If
End If
End Sub
However, a better solution might be to use formulas (such as an array formula or using INDEX and MATCH) in the target worksheets to extract the data - this will avoid using a macro entirely.