設計模式 C#：抽象工廠模式實作 - 產品介面與抽象工廠 (中)

抽象工廠模式核心抽象層定義：

抽象產品介面

public abstract class AbstractMessage {
    public abstract string Insert(AbstractMessageModel amm);
}

public abstract class AbstractMessageModel {
    public string Message { get; set; }
    public DateTime PublishTime { get; set; }
    public abstract string UserId { get; set; }
}

具體產品模型

public class SqlMessageModel : AbstractMessageModel {
    private string _userId;
    public override string UserId { get => _userId; set => _userId = value; }
    // 建構子略...
}

public class XMLMessageModel : AbstractMessageModel {
    private string _userId;
    public override string UserId { get => _userId; set => _userId = value; }
    // 建構子略...
}

抽象工廠介面

public abstract class AbstractMessageFactory {
    public abstract AbstractMessageModel CreateMessageModel();
    public abstract AbstractMessage CreateMessage();
}

定義兩個產品族（MessageModel、Message）的建立契約，具體工廠負責實例化對應具體類別。