现有的实例变量＆＃39; PadControllerDelegate＆＃39;对于财产＆＃39; PadControllerDelegate＆＃39;使用assign属性必须是_unsafe_unretained

Question

@interface wisepadViewController : UIViewController <PadControllerDelegate> {
@private
    id<PadControllerDelegate> PadControllerDelegate;
}

@property (nonatomic, assign) id<PadControllerDelegate> PadControllerDelegate;

现在在.m文件中我做了

@implementation wisepadViewController


@synthesize PadControllerDelegate;

如何修复它，无法做到。问题出在哪里。