c# - 如何在 C# 中使用 LINQ 搜索特定字符串属性的对象列表

Question

我有以下代码:

    private List<Car> Fleet = new List<Car>()
    {
       new Car("Toyota", "Corola","YI348J", 2007, 7382.33),
       new Car("Renault", "Megane","ZIEKJ", 2001, 1738.30),
       new Car("Fiat", "Punto","IUE748", 2004, 3829.33)
    };

    public void addToFleet(String make, String model, String registration, int year, Double costPrice)
    {
        Fleet.Add(new Car(make, model, registration, year, costPrice));
    }

在将新的 Car 对象添加到 Fleet 列表之前，我需要检查“注册”是否已作为列表中任何 Car 对象的属性存在。此检查需要使用 LINQ 并在 addToFleet 方法中进行。

Answer 1

假设您的 Car 类有一个属性注册:

private List<Car> Fleet = new List<Car>()
{
   new Car("Toyota", "Corola","YI348J", 2007, 7382.33),
   new Car("Renault", "Megane","ZIEKJ", 2001, 1738.30),
   new Car("Fiat", "Punto","IUE748", 2004, 3829.33)
};

public void addToFleet(String make, String model, String registration, int year, Double costPrice)
{
    if(Fleet.Any(car => car.Registration == registration))
    {
       // already in there
    } 
    else
    {
      Fleet.Add(new Car(make, model, registration, year, costPrice));
    }
}