c# - 如何将基类型列表转换为派生类型列表

Question

似乎有很多问题从派生类到基类，但我的问题是如何将基类型列表转换为派生类型列表？

public class MyBase {
    public int A;
}

public class MyDerived : MyBase {
    public int B;
}

public void MyMethod() {
    List<MyBase> baseCollection = GetBaseCollection();
    List<MyDerived> derivedCollection = (List<MyDerived>)baseCollection; // Which doesn't work
}

我最终得到的解决方案不是很优雅。

public class MyBase {
    public int A;
}

public class MyDerived {
    public int B;
    public MyBase BASE;
}
public void MyMethod() {
    List<MyBase> baseCollection = GetBaseCollection();
    List<MyDerived> derivedCollection = new List<MyDerived>();
    baseCollection.ForEach(x=>{
        derivedCollection.Add(new derivedCollection(){ BASE = x});
    });
}

一定有更好的方法...

Answer 1

您可以使用 Linq 方法 OfType<MyDerived>() ，例如:

List<MyDerived> derivedCollection = baseCollection.OfType<MyDerived>().ToList();

它将删除所有不是 MyDerived 的项目虽然类