Dan Wood: The Eponymous Weblog (Archives)

Here is a snippet of code you can put into any subclass of NSValueTransformer that will cause it to automatically register itself when the class is loaded. This is useful for almost all value transformers, except perhaps those that you need to be given a parameter in the initialization process, such as these cool transformer classes.

This code will just cause the transformer to be registered with the name of the class itself. So if you class was, for instance, CondenseTransformer then you would specify "CondenseTransformer" in your nib file.

+ (void)load
{
  NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
  NSValueTransformer *theTransformer = [[[self alloc] init] autorelease];
  [NSValueTransformer setValueTransformer:theTransformer
         forName:NSStringFromClass([self class])];
  [pool release];
}