如何做单继承 [英] How to do inheritance with singleton

问题描述

我想知道如何从一个具有一个单类BaseClient继承并能够在继承类使用基本成员相同的实例从基类单身了。

I want to know how to inherit from a class 'BaseClient' that has a singleton and be able to use same instance of basic members from base class singleton in the inherited class too.

public class BaseClient
{
    protected string _url;
    protected string _username;
    protected string _password;

    private static BaseClient _instance;
    private static readonly object padlock = new object();

    public static BaseClient Instance
    {
        get
        {
            lock (padlock)
            {
                if (_instance == null)
                {
                    _instance = new BaseClient(true);
                }
                return _instance;
            }
        }
    }

    public void SetInfo(string url, string username, string password)
    {
        _url = url;
        _username = username;
        _password = password;
    }

    public string GetVersion()
    {
        //MyService is a simple static service provider
        return MyService.GetVersion(_url, _username, _password);
    }
}

public class Advanced : BaseClient
{
    private static AdvancedClient _instance;
    private static readonly object padlock = new object();

    public static AdvancedClient Instance
    {
        get
        {
            lock (padlock)
            {
                if (_instance == null)
                {
                    _instance = new AdvancedClient(true);
                }
                return _instance;
            }
        }
    }

    public void DoAdvancedMethod()
    {
        MyService.DoSomething(_url, _username, _password);
    }
}

所以，如果我用BaseClient.Instance.SetInfo（的http：// myUrl，MYUSER，MYPASSWORD）;然后AdvancedClient.Instance.DoAdvancedMethod（）时，AdvancedClient单将使用相同的基本成员实例作为BaseClient单身？

So if I use BaseClient.Instance.SetInfo("http://myUrl", "myUser", "myPassword"); and then AdvancedClient.Instance.DoAdvancedMethod(), the AdvancedClient singleton will use the same base member instance as the BaseClient singleton?

推荐答案

只是开个玩笑:)这里是我的解决方案：

Just kidding :) here's my solution:

我简单地使用一个独立的类来存储共享的成员，并在AdvancedClient单创建，检索BaseClient有一个

I simply use an independent class to store the shared members and on AdvancedClient singleton creation, retrieve the BaseClient one.

public class ClientInfo
{
    public string Url { get; set; }
    public string Username { get; set; }
    public string Password { get; set; }
}

public class BaseClient
{
    protected ClientInfo _info;

    private static BaseClient _instance;
    private static readonly object padlock = new object();

    public static BaseClient Instance
    {
        get
        {
            lock (padlock)
            {
                if (_instance == null)
                {
                    _instance = new BaseClient(true);
                }
                return _instance;
            }
        }
    }

    public ClientInfo Info
    {
        get
        {
            if(_info == null)
            {
                _info = new ClientInfo();
            }

            return _info;
        }
    }

    public void SetInfo(string url, string username, string password)
    {
        Info.Url = url;
        Info.Username = username;
        Info.Password = password;
    }

    public string GetVersion()
    {
        //MyService is a simple static service provider
        return MyService.GetVersion(Info.Url, Info.Username, Info.Password);
    }
}

public class Advanced : BaseClient
{
    private static AdvancedClient _instance;
    private static readonly object padlock = new object();

    public static AdvancedClient Instance
    {
        get
        {
            lock (padlock)
            {
                if (_instance == null)
                {
                    _instance = new AdvancedClient(true);
                    _instance._info = BaseClient.Instance.Info;
                }
                return _instance;
            }
        }
    }

    public void DoAdvancedMethod()
    {
        MyService.DoSomething(Info.Url, Info.Username, Info.Password);
    }
}

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