相关疑难解决方法(0)

Visual Studio允许通过自动生成的访问器类对私有方法进行单元测试.我编写了一个成功编译的私有方法的测试,但它在运行时失败了.一个相当小的代码和测试版本是:

//in project MyProj
class TypeA
{
    private List<TypeB> myList = new List<TypeB>();

    private class TypeB
    {
        public TypeB()
        {
        }
    }

    public TypeA()
    {
    }

    private void MyFunc()
    {
        //processing of myList that changes state of instance
    }
}    

//in project TestMyProj           
public void MyFuncTest()
{
    TypeA_Accessor target = new TypeA_Accessor();
    //following line is the one that throws exception
    target.myList.Add(new TypeA_Accessor.TypeB());
    target.MyFunc();

    //check changed state of target
}

运行时错误是:

Object of type System.Collections.Generic.List`1[MyProj.TypeA.TypeA_Accessor+TypeB]' cannot be converted to type …