iOS中的日期选择器控制器

我想在我的应用程序中使用日期选择器。但当我从日期选择器中选择日期时，此代码显示异常。异常为

[AppointViewController PickerAction:]：已发送无法识别的选择器 到实例0x7fbbfa5f9d60'

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您必须为日期选择器实现选择器方法，如下所示：

UIDatePicker*myPicker=[[UIDatePicker alloc]init]

myPicker.datePickerMode = UIDatePickerModeDate;
myPicker.minimumDate = [NSDate dateWithTimeIntervalSince1970:0];
myPicker.maximumDate = [NSDate date];
[myPicker addTarget:self action:@selector(datePickerValueChanged:)
 forControlEvents:UIControlEventValueChanged];
 NSDate *mydate = myPicker.date;
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init];
[dateFormatter setDateFormat:@"dd/MM/yyyy"];
[self.txtDOB setInputView:myPicker];

• （无效）datePickerValueChanged:（id）发件人{ UIDatePicker*picker=（UIDatePicker*）发送方； NSString*日期字符串
  NSDate*mydate=picker.date； NSDateFormatter*dateFormatter=[[NSDateFormatter alloc]init]； [日期格式化程序setDateFormat:@“dd/MM/yyyy”]； dateString=[dateFormatter stringFromDate:mydate]； [self.txtDOB setText:dateString]； }

可能的副本

myPicker.datePickerMode = UIDatePickerModeDate;
myPicker.minimumDate = [NSDate dateWithTimeIntervalSince1970:0];
myPicker.maximumDate = [NSDate date];
[myPicker addTarget:self action:@selector(datePickerValueChanged:)
 forControlEvents:UIControlEventValueChanged];
 NSDate *mydate = myPicker.date;
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init];
[dateFormatter setDateFormat:@"dd/MM/yyyy"];
[self.txtDOB setInputView:myPicker];