你可以使用这个概念关联对象。使用函数 objc_setAssociatedObject（）和 objc_getAssociatedObject（）。您可以使用这些属性实质上添加一个新属性，在您的情况下，通过类别将 NSDictionary 保存到对象。

You can use the concept of associated objects. Using the functions objc_setAssociatedObject() and objc_getAssociatedObject(). You can use these properties to essentially add a new property, in your case to hold an NSDictionary, to an object through a category.

以下是 UIAlertView 类别的示例。如果项目使用ARC，则应在没有 ARC ， -fno-objc-arc 标志的情况下编译这些文件。

Here is an example of a UIAlertView category. These files should be compiled without ARC, -fno-objc-arc flag set if the project is using ARC.

UIAlertView + WithContext.h：

#import <UIKit/UIKit.h>
@interface UIAlertView (Context)
@property (nonatomic, copy) NSDictionary *userInfo;
@end

UIAlertView + WithContext.m：

#import "UIAlertView+WithContext.h"
// This enum is actually declared elseware
enum {
    OBJC_ASSOCIATION_ASSIGN = 0,
    OBJC_ASSOCIATION_RETAIN_NONATOMIC = 1,
    OBJC_ASSOCIATION_COPY_NONATOMIC = 3,
    OBJC_ASSOCIATION_RETAIN = 01401,
    OBJC_ASSOCIATION_COPY = 01403
};
@implementation UIAlertView (Context) 
static char ContextPrivateKey;
-(void)setUserInfo:(NSDictionary *)userInfo{
    objc_setAssociatedObject(self, &ContextPrivateKey, userInfo, 3);
}
-(NSDictionary *)userInfo{
    return objc_getAssociatedObject(self, &ContextPrivateKey);
}
@end

此类别很容易使用。

SomeViewController.m： a UIAlertViewDelegate 是否使用ARC。

SomeViewController.m: a UIAlertViewDelegate using ARC or not.

-(void)viewDidAppear:(BOOL)animated{
    [super viewDidAppear:animated];
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Title" message:@"Message" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
    alert.userInfo = [NSDictionary dictionaryWithObject:@"Hello" forKey:@"Greeting"];// autorelease if MRC
    [alert show]; // release if MRC
}

-(void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex{
    NSLog(@"userInfo:%@",alertView.userInfo);
}

当你按下alertview的OK按钮时，你会看到：

When you press the alertview's OK button you will see:

userInfo:{
    Greeting = Hello;
}

几个笔记：

1）确保关联类型与属性声明匹配，以便事物按预期运行。

1) Make sure the association type matches the property declaration so things behave as expected.

2）你可能不应该使用属性/关联的userInfo 因为Apple可能决定将 userInfo 属性添加到 UIAlertView 将来。

2) You probably shouldn't use userInfo for the property/association since Apple may well decide to add a userInfo property to UIAlertView in the future.

编辑 解决您对 [self autorelease]的担忧;

必须平衡隐含的 alloc 保留此行：委托：[[WantAlertViewContext alloc] initWithDelegate：self context：userInfo] 。您可以通过在最终 UIAlertView 委托方法中调用 [self autorelease]; 来实现此平衡。

It is imperative that you balance your implicit alloc retain from this line: delegate:[[WantAlertViewContext alloc] initWithDelegate:self context:userInfo]. You achieve this balance by calling [self autorelease]; in the final UIAlertView delegate method.

当然，这确实是错的。主要是因为在看这个时没有办法乍一看它看起来像内存管理错误。但有一种简单的方法可以避免您正在创建的受控泄漏API;让 WantAlertViewContext 的实例明确保留自己。例如：

Granted, this does feel wrong. Mostly because there is no way when looking at this that it doesn't at first blush look like memory mis-management. But there is one simple way to avoid this "controlled leak" API you are creating; Have the instance of WantAlertViewContext explicitly retain itself. For example:

-(id)initWithDelegate:(id<WantAlertViewContextDelegate>)delegate context:(id)context{
    self = [super init];
    if (self) {
        _delegate = delegate;
        _context  = [context retain];
    }
    return [self retain]; // Explicitly retain self
}

-(void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex{
    alertView.delegate = nil;
    [self autorelease]; // Or just [self release]; doesn't make much difference at this point
}

现在你的班级有一些内在的和谐。我说一些，因为这仍然不完美。例如，如果实例永远不是警报视图委托，则永远不会释放它。它仍然只是一个半控制的内存泄漏。

Now your class has some internal harmony. I say some because this is still not perfect. For example, if an instance is never an alert-view delegate it will never be released. It is still just a "semi-controlled" memory leak.

无论如何，现在你的实例化调用看起来更合乎逻辑：

Anyway, now your instantiation call can look more logical:

delegate:[[[WantAlertViewContext alloc] initWithDelegate:self context:userInfo] autorelease];

我认为这种特殊的设计模式充满了危险。如果你最终使用它，请密切关注它。

I think that this particular design pattern is fraught with danger. If you do end up using it keep a close eye on it.