The only thing I’m doing differently to yours is setting the custom cell in awakeFromNib, because I’m using a non document based app, so can’t use windowControllerDidLoadNib…

- (void)awakeFromNib {
// Set next responder for this view so we can intercept delete key presses
[mainView setNextResponder:self];

// Set up custom cell for table view
EmployeeTableCell *statusCell = [[EmployeeTableCell alloc] init];
[statusTableColumn setDataCell:statusCell];
}

Thanks for the speedy reply. Appreciate your help. I had thought the same thing, why it is trying to use a placeholder when I haven’t set one up and I’m using a NSCell? However there’s definitely no place holder set.

To check I just added a brand new column to my table, set the binding to clientDictionary and all is ok. But then I change the NSTableColumn type to be my CustomCell class, and it crashes with the setPlaceHolderString error.

It’s just too weird!

Any other ideas?

Thanks again.

This is a great tutorial and the clearest I’ve found on this subject. So thank you for that. However! I am having a spot of difficulty despite believing I’ve followed the steps to the letter in my own project.

I get up to the part where you bind to the personDictionary in Interface Builder. I’ve defined personDictionary both in my model and also added the various required functions to the custom managedObject class code. When I run the project, I get the following error and crash:

[CustomCell setPlaceholderString:]: unrecognized selector sent to instance 0x100637f20

If I unbind the personDictionary from the table column or change it back to the NSString firstName, the error goes away.

Do you have any ideas what might be happening or pointers of where to look for problems. This has me stumped!

Appreciate your time.

Thanks,

Gareth.

It should read -(void)set_YourClassName_Dictionary. Re-add the setter that you removed in Tim’s original tutorial.

1. I subclassed NSTextFieldCell, rather than NSCell. (I’m not sure yet how to do this with just NSCell. In my case I have a name, and some read only metadata about the object I am displaying, so this works fine for me.)

2. Add the following to your NSManagedObject subclass (PersonObject in your example):

-(void)setDictionary
{
[self setValuesForKeysWithDictionary:aDictionary];
}

3. Subclass NSFormatter with the following methods (these are the minimum required to subclass NSFormatter, according to the documentation)

- (BOOL)getObjectValue:(id *)anObject forString:(NSString *)string errorDescription:(NSString **)error
{
if (anObject){
*anObject = [NSDictionary dictionaryWithObject:string forKey:@"name"];
return YES;
}
return NO; // This probably shouldn’t happen…Could be a bindings issue if it does?
}
- (NSString *)stringForObjectValue:(id)anObject
{
if (![anObject isKindOfClass:[NSDictionary class]])
return nil;
return [anObject valueForKey:@"name"]; // This will propagate back to your NSManagedObject subclass, since we created setDictionary.
}
- (NSAttributedString*)attributedStringForObjectValue:(id)anObject withDefaultAttributes:(NSDictionary *)attrs
{
if (![anObject isKindOfClass:[NSDictionary class]])
return nil;
NSAttributedString * anAttributedString = [[NSAttributedString alloc]initWithString: [anObject valueForKey:@"name"]];

return anAttributedString;
}

4. Add the following to your NSTextFieldCell’s awakeFromNib:
MyFormatter * aMyFormatter = [[[MyFormatter alloc]init]autorelease];
[self setFormatter:aMyFormatter];

That should be it, if I didn’t leave out any steps… I hope this helps someone, and if you spot anything that can be improved in my code, please post a followup!
-Tim

Great tutorial. Just what I needed to kick start my custom TableView. Wish I had known about the Managed Object Class Generator before I hand-cranked four classes last week! Thanks also to Simon Wolf for his non-GC comments – I’m not using GC either (yet).

A few of things I did differently are below. Two were because I’m not using Garbage Collection.

1. Let the Managed Object Class Generator create Objective-C 2.0 properties so that there was less code around. I then simply changed the UNKNOWN_TYPE to NSDictionary and added the custom getter method.

2. In the getter for the NSDictionary I generated an auto-releasing dictionary with an auto-releasing array:
return [self dictionaryWithValuesForKeys:[NSArray arrayWithObjects:@"firstName", @"lastName", @"department", @"salary", nil]];

3. In MyDocument.m I released infoCell:
EmployeeTableCell *infoCell = [[EmployeeTableCell alloc] init];
[peopleTableColumn setDataCell:infoCell];
[infoCell release];