Returns the current value for an input port.
Original signature is '- (id) valueForInputKey:(NSString*)key'
Available in Mac OS X v10.5 and later.
- key (NSString)
- The key for the input port you want to check.
The value associated with the key or nil if called outside of the execute:atTime:withArguments: method.
- Available in Monobjc Bridge: 10.6 (For Mac OS X 10.6 and later), 10.5 (For Mac OS X 10.5 and later)