What is key-value coding ?

The idea behind key-value coding is pretty simple: instead of directly getting and setting specific properties on an object, key-value coding involves passing in a "key" (usually a string) and getting or setting the property associated with that key.


For example:
// Set a property directly...
someObject.someProperty = someValue;

// ...or set the same property using key-value coding
[someObject setValue:someValue forKey:@"someProperty"];