How do I find all the property keys of a KVC compliant Objective-C object?

Question

Is there a method that returns all the keys for an object conforming to the NSKeyValueCoding protocol?

Something along the lines of [object getPropertyKeys] that would return an NSArray of NSString objects. It would work for any KVC-compliant object. Does such a method exist? I haven't found anything in searching the Apple docs so far.

Thanks, G.

Answer 1

#import "objc/runtime.h"  unsigned int outCount, i;  objc_property_t *properties = class_copyPropertyList([self class], &outCount); for(i = 0; i < outCount; i++) {     objc_property_t property = properties[i];     const char *propName = property_getName(property);     if(propName) {             const char *propType = getPropertyType(property);             NSString *propertyName = [NSString stringWithUTF8String:propName];             NSString *propertyType = [NSString stringWithUTF8String:propType];     } } free(properties); 

Answer 2

Use class_getPropertyList. That will tell you all the @properties of the object.

It won't necessarily list every KVC-compliant property, because any method that takes no arguments and returns a value is a valid KVC-compliant getter. There's no 100%-reliable way for the runtime to know which ones behave as properties (e.g., -[NSString length]) and which ones behave as commands (e.g., -[NSFileHandle readDataToEndOfFile]).

You should be declaring your KVC-compliant properties as @properties anyway, so this shouldn't be too big of a problem.