CODEWITHSUNDEEP
objective-c
JoJo
JoJo

Reputation: 20115

Request for member in something not a structure or union

Here's some background on my program: [self.channels] is an array of Channel objects. Each Channel object has a synthesized string called channelId.

Compiles

Channel *channel = [self.channels objectAtIndex:indexPath.row];
NSString *channelId = channel.channelId;

Does not compile

NSString *channelId = [self.channels objectAtIndex:indexPath.row].channelId;
// Request for member 'channelId' in something not a structure or union

Why couldn't I chain my commands to get the channelId property? The two versions of my code look the same...

Upvotes: 1

Views: 1382

Answers (1)

Ripred
Ripred

Reputation: 157

In your first version the compiler knows what kind of object you are working with since it is using a Channel* variable to reference the data member. In your second version the compiler only knows that an NSObject may be returned but has no immediate knowledge that the returned object will be of a certain class. You can change this by casting the returned value:

NSString *channelId = ((Channel*)[self.channels objectAtIndex:indexPath.row]).channelId;

Upvotes: 3

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