Question

我有 ObservableCollection <> 这样的自定义对象

public class Employee()
{
    public int id { get; set; }
    public decimal salary { get; set; }
}

ObservableCollection<Employee> employeeCollection = new ObservableCollection<Employee>()
{
    new Employee() { id = 1, salary = 1000.00 },
    new Employee() { id = 2, salary = 1500.00 },
    new Employee() { id = 3, salary = 2000.00 },
    new Employee() { id = 4, salary = 2500.00 },
    new Employee() { id = 5, salary = 3000.00 }
};

id是此集合中的唯一属性。如何根据ID更新收款人的薪水，并以最有效的方式获取整个收款人？

即：如果我将ID为3的员工的薪水更新为5000.00，则结果必须是这样

employeeCollection = new ObservableCollection<Employee>()
{
    new Employee() { id = 1, salary = 1000.00 },
    new Employee() { id = 2, salary = 1500.00 },
    new Employee() { id = 3, salary = 5000.00 },
    new Employee() { id = 4, salary = 2500.00 },
    new Employee() { id = 5, salary = 3000.00 }
}

我需要使用更新后的值来获取整个集合。

Answer 1

var emp = employeeCollection.FirstOrDefault(x => x.Id == 3)
if(emp != null) // might not exist
   emp.salary = 5000

如果您需要处理一组记录

var results = employeeCollection.Where(x => x.Id == 3)

foreach(var emp in results)
   emp.salary = 5000

或

employeeCollection.Where(x => x.Id == 3)
                  .ToList()
                  .ForEach(x => x.salary = 5000);

我个人不喜欢第二种方法 h

其他资源

Enumerable.FirstOrDefault Method

返回序列的第一个元素，如果未找到任何元素，则返回默认值。

如何使用C＃通过其ObservableCollection的ID更新？

1 个答案: