Vlookup in VBA using variable as datasheet

Hi,

I'm trying to create the below lookup in VBA using a variable as the datasheet to lookup to. I get an error of "Object does not support this Property or Method" any ideas why

Sub lookuptoanothersheet()
Dim wbkmain As Workbook
Dim wbkdatasheet As Workbook

Set wbkmain = ThisWorkbook

Set wbkdatasheet = Workbooks.Open("C:\Users\james\Documents\VBA\example.xlsx")

wbkmain.Worksheets(1).Range("b1").Formula = "vlookup(A1,[" & wbkdatasheet & "]Table1!A1:C200,2,0)"


    
End Sub