New topic: FolderItem question
<http://forums.realsoftware.com/viewtopic.php?t=31359> Page 1 of 1 [ 6 posts ] Previous topic | Next topic Author Message serd83 Post subject: FolderItem questionPosted: Tue Dec 01, 2009 8:15 pm Joined: Thu Feb 22, 2007 7:08 pm Posts: 767 Assume there is a folder in the applications order with the name "Main". In this "Main" folder are again a order with the name "Order 2", and in this are some files, etc. When I want check a file for nil, but the "Main" was renamed or deleted, so I become for this a nil: Code:dim f as folderitem = specialfolder.applications.child("Main").child("Order 2").child("aFile.txt") The "only way" I found is to check before if the order exist. Or miss I a function for this? Code:dim f as folderitem dim par as folderitem = specialfolder.applications.child("Main").child("Order 2") if par <> nil and par.exists = true then f = specialfolder.applications.child("Main").child("Order 2").child("aFile.txt") Top JShaffer Post subject: Re: FolderItem questionPosted: Tue Dec 01, 2009 8:46 pm Joined: Fri Jan 23, 2009 9:18 am Posts: 18 Location: Summerfield, Florida I saved this code snippet that might be of use. I'm not sure of whom to credit for the code. // Set up folder path dim fPath() as string = Array("Programming Data","Folder 1","Folder 2") // Base FolderItem dim f as FolderItem = SpecialFolder.Documents // Search for each folder for each fName as string in fPath f = f.Child(fName) if f = nil or not f.Exists then f.CreateAsFolder // will add the missing folders // or error code end next HTH Jim Top timhare Post subject: Re: FolderItem questionPosted: Wed Dec 02, 2009 1:17 am Joined: Fri Jan 06, 2006 3:21 pm Posts: 6882 Location: Portland, OR USA Quote:The "only way" I found is to check before if the order exist. Or miss I a function for this? That is the only way. Any time you chain more than 2 folderitems together like that, you are susceptible to a nilobject exception. If there is ever any question, you should handle each node in the path one at a time. Top applesource Post subject: Re: FolderItem questionPosted: Wed Dec 02, 2009 6:23 am Joined: Thu Aug 06, 2009 2:25 pm Posts: 214 Location: Oregon Is the proper way, then, to build a folderitem one folder at a time and check for nil each time, like this? Code:dim f as folderitem f=SpecialFolder.Preferences.child("My App") if not (f is nil) and f.exists then f=f.child("Second Folder") if not (f is nil) and f.exists then f=f.child("Third Folder") // which leaves us with f pointing to "preferencesfolder/my app/second folder/third folder" Is this the correct technique? _________________ AppleSource Software http://www.applesource.biz Top serd83 Post subject: Re: FolderItem questionPosted: Wed Dec 02, 2009 1:44 pm Joined: Thu Feb 22, 2007 7:08 pm Posts: 767 Thanks for the answers. As you see you can use different techniques for this. Important is that you should be careful when you chain more than 2 folderitems together, as Tim said. It is logical, but it can happen that you want do anything with a file and use: Code:dim f as folderitem = specialfolder.applications.child("Main").child("Folder 2").child("aFile.txt") if f <> nil and f.exists = true then f.launch But it can happen that the user change for example the "Main" folder name and you become a nil for this: Code:dim f as folderitem = specialfolder.applications.child("Main").child("Folder 2").child("aFile.txt") Top npalardy Post subject: Re: FolderItem questionPosted: Wed Dec 02, 2009 1:55 pm Joined: Sat Dec 24, 2005 8:18 pm Posts: 5455 Location: Canada, Alberta, Near Red Deer serd83 wrote:Code:dim f as folderitem = specialfolder.applications.child("Main").child("Folder 2").child("aFile.txt") The problem here is 1) ifapplications folder is missing (it can happen) then everything after that is not going to work and you will get a nil object exception 2) if main is missing then everything after that is not going to work and you will get a nil object exception 3) if Folder 2 is missing then everything after that is not going to work and you will get a nil object exception you can wrap it in a nil object exception handler (see try ... catch) or other error checking as appropriate _________________ My web site Great White Software RBLibrary.com REALbasic learning Top Display posts from previous: All posts1 day7 days2 weeks1 month3 months6 months1 year Sort by AuthorPost timeSubject AscendingDescending Page 1 of 1 [ 6 posts ] -- Over 1500 classes with 29000 functions in one REALbasic plug-in collection. The Monkeybread Software Realbasic Plugin v9.3. http://www.monkeybreadsoftware.de/realbasic/plugins.shtml [email protected]
