Dim result As XLReaderResult = XL.Reader.ReadSheetByName(File.DirAssets, "Todo List.xlsx", "Sheet1")
' Dim result As XLReaderResult = XL.Reader.ReadRange(File.DirAssets, "Todo List.xlsx", "Sheet1") <---- This is an error
The problem is mainly that reading Sheet1 should be ReadSheetByName instead of ReadRange
You should also check for other errors in your code.