如何更新核心数据输入值

问题描述

[newVehicle setValue: _txtFieldVehicleNumber.text forKey:@"number"];

[newVehicle setValue: lblFuelType.text forKey:@"fueltype"];

[newVehicle setValue: lblFuelUnit.text forKey:@"fuelunit"];

[newVehicle setValue: lblDistanceUnit.text forKey:@"distanceunit"];

我想更新名为Vehicle"的核心数据实体，对于该实体，我有几个属性，当我从实体中选择特定属性时，我想更新其中一些属性，但不是全部.那我该怎么办??

I want to update my core data entity named "Vehicle", for that entity I have several attributes and I want to update some of them but not all when I select particular attribute from the entity. So what should I do ??

推荐答案

您可以执行以下操作(近似代码.实现错误处理和检查语法).

you can do the following (approximate code. Implement error handling and check syntax).

NSFetchRequest *fetchRequest=[NSFetchRequest fetchRequestWithEntityName:@"Vehicle"];
NSPredicate *predicate=[NSPredicate predicateWithFormat:@"vehicle_id==%@",vehicle_id]; // If required to fetch specific vehicle
fetchRequest.predicate=predicate;
Vehicle *newVehicle=[[self.managedObjectContext executeFetchRequest:fetchRequest error:nil] lastObject];

[newVehicle setValue: _txtFieldVehicleNumber.text forKey:@"number"];

[newVehicle setValue: lblFuelType.text forKey:@"fueltype"];

[newVehicle setValue: lblFuelUnit.text forKey:@"fuelunit"];

[newVehicle setValue: lblDistanceUnit.text forKey:@"distanceunit"];

[self.managedObjectContext save:nil]