首先：调用非虚拟构造函数中的方法。你在哪里读到那里？ （注意：调用 方法可能是一个问题;它不是一个自动的no-no，但你需要非常仔细地观察你在做什么。）

First off: there is nothing wrong with calling non-virtual methods in the constructor. Where did you read that there was? (Note: calling virtual methods can be a problem; it is not an automatic no-no, but you need to watch what you are doing very carefully).

另外，每次 GenerateRandomNumber $时生成一个新的随机 c $ c>被调用。您可以将 Random 实例提取到字段以修复：

As an aside, it seems wasteful to generate a new Random instance every time GenerateRandomNumber is called. You can extract the Random instance to a field to fix that:

class RandomNumberHandler
{
    private readonly Random random = new Random();
    private int randomNumber;

    public RandomNumberHandler()
    {
        this.randomNumber = GenerateRandomNumber();
    }

    private int GenerateRandomNumber()
    {
        return this.random.Next(3000) + 1000;
    }
}

但这又引出了另一个问题：if GenerateRandomNumber 在每个实例的生命周期（在构造函数中）只调用一次，那么创建一个新的 Random 每个对象。因此，下一个逻辑步骤是使 random 为 static 。这意味着 GenerateRandomNumber 也可以变成 static （确实，它必须）：

But this raises another question: if GenerateRandomNumber is only called once in each instance's lifetime (in the constructor), then it doesn't make sense to create a new Random for each object. So the next logical step is to make random be static. This means that GenerateRandomNumber can also become static (and indeed, it has to):

class RandomNumberHandler
{
    private static readonly Random Random = new Random();
    private int randomNumber;

    public RandomNumberHandler()
    {
        this.randomNumber = GenerateRandomNumber();
    }

    private static int GenerateRandomNumber()
    {
        return Random.Next(3000) + 1000;
    }
}