EnableExplicit

Define File$
Define info.SHFILEINFO

File$ = OpenFileRequester("","","Alle Dateien|*.*", 0)
If File$
  If SHGetFileInfo_(@File$, 0, @info.SHFILEINFO, SizeOf(SHFILEINFO), #SHGFI_TYPENAME)
    MessageRequester("","Dateityp-Bezeichnung: "+PeekS(@info\szTypeName, 80),0)
  EndIf
EndIf