objective-c - NSMutableDictionary 不检索对象

Question

EmployeesArray = [[NSMutableArray alloc] initWithCapacity:100];
    Employees *Emp1 = [[Employees alloc] init];    
    Emp1.Number = 1;
    Emp1.Name = @"Jamal";
    Emp1.Age = 16;
    Emp1.Gender = @"Male";
  [EmployeesArray addObject:Emp1];
 [Dic1 setValue:Emp1 forKey:@"A"];

- (IBAction)Retrieve:(id)sender {

  Employees *objEmp2 = [Dic1 valueForKey:@"A"];
    printf(objEmp2.Name);

}

为什么这段代码没有检索到名字？？并出现错误？？

Answer 1

你有没有初始化Dic1字典？

// try doing this
Dic1 = [[NSMutableDictionary alloc] init];

EmployeesArray = [[NSMutableArray alloc] initWithCapacity:100];
    Employees *Emp1 = [[Employees alloc] init];    
    Emp1.Number = 1;
    Emp1.Name = @"Jamal";
    Emp1.Age = 16;
    Emp1.Gender = @"Male";
  [EmployeesArray addObject:Emp1];
 [Dic1 setObject:Emp1 forKey:@"A"];

- (IBAction)Retrieve:(id)sender {

  Employees *objEmp2 = [Dic1 objectForKey:@"A"];
    printf(objEmp2.Name);

}