App.Path in Excel

What is the equivalant of App.Path in VBA programming with Excel? I've tried Me.Path inside the ThisWorkbook module, even tried Workbooks(1).Path but they all return vbNullString.

Sub a()
MsgBox ThisWorkbook.Path


End Sub

or activeworkbook.path

You can also use....

Code:

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Set objExcel = CreateObject("Excel.Application")
Set oXLApp = objExcel.Workbooks.Open(FileName:=App.Path & "\" & "Book1.xls")

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