objective-c - block變數怎麼變成全域變量

Question

外部有個全域變數self.array

dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);

dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
NSString *string=@"变量"；

}
NSlog(@"%@",self.array); //此處self.array為空
請問下要怎麼給self.array賦值呢？