Var csvType As New FileType
followed by some filled properties, then a Break after the user selected a csv file.
I only wanted to see what csvType properties are filled (by me / by Xojo / Tahoe):
Once in the debugger I clicked in:

and get:
Just curious.
Define your FileType in the IDE using the FileType editor. Then use that when presenting the FileOpenDialog by assigning the FileType(s) to the dialog’s Filter property:
oFileOpen = New OpenFileDialog
oFileOpen.Filter = SomeFileTypeSet.SomeType
oFItem = oFileOpen.ShowModal