从基类序列化和反序列化派生类 [英] Serialize and DeSerialized derived classes from the base class

问题描述

我试图创建一个基类，可以从中继承基类（向派生类添加属性），并从基类中利用Load和Save方法。我发现自己写了Load and Save一遍又一遍，我想对它应用一些DRY ...

I am trying to create a base class where I can inherit from it (to add properties to the derived classes) and the utilized the Load and Save methods from the base class. I find myself writing the Load and Save over and over and I'd like to apply some DRY to it...

namespace Common

{
  using System;
  using System.IO;
  using System.Xml.Serialization;

  public abstract class ApplicationSettings
  {
    protected ApplicationSettings()
    {
    }

    public static ApplicationSettings Load(string fileName)
    {
      if (!File.Exists(fileName))
      {
        return null;
      }

      XmlSerializer serializer = new XmlSerializer(typeof(ApplicationSettings));

      using (StreamReader reader = new StreamReader(fileName))
      {
        ApplicationSettings param = (ApplicationSettings)serializer.Deserialize(reader);
        reader.Close();
        return param;
      }
    }

    public void Save(string fileName)
    {
      XmlSerializer serializer = new XmlSerializer(typeof(ApplicationSettings));
      using (StreamWriter writer = new StreamWriter(fileName))
      {
        serializer.Serialize(writer, this);
        writer.Close();
      }
    }
  }
}

给出这个抽象类，然后我想派生一个类，例如：

Given this abstract class, I then want to derive a class such as:

namespace Common
{
  using System;

  public class ApplicationParameters : ApplicationSettings
  {
    public ApplicationParameters()
    {
    }
    public string AuthorizationCode
    {
      get;
      set;
    }
    public string ReferenceNumber
    {
      get;
      set;
    }
  }
}

对于派生类，我应该能够执行以下操作

For the Derived class, I should be able to do something like

ApplicationParameters参数=
ApplicationParmeters.Load（ settings.xml）;

ApplicationParameters parameters = ApplicationParmeters.Load("settings.xml");

但是，在上面的实现中，当我在调用Load方法时尝试将ApplicationSettings转换为ApplicationParameters类时，会发生编译器错误。

However, in the implementation above, an compiler error occurs when I attempt to cast the ApplicationSettings to the ApplicationParameters class when I call the Load method in the base class.

有没有办法做到这一点？

Is there a way to do this?

推荐答案

使顶级类通用，以便Save / Load方法可以支持多种类型：

Make the top level class generic so that the Save/Load methods can support multiple types:

public abstract class ApplicationSettings<T>
{
    public static T Load(string xml){ // Implementation }

    public static void Save (T obj) { // Implementation }
}

public class ApplicationParameters : ApplicationSettings<ApplicationParameters>
{
}

或者您也可以使静态方法本身通用：

Or you could just make the static methods themselves generic:

public abstract class ApplicationSettings
{
    public static T Load<T>(string xml){ // implementation }

    public static void Save<T>(T obj){ // implementation }
}

现在您将注意到，抽象父类的Save / Load方法被强力键入到子级，因此以下行将按预期工作：

You will now notice that the Save/Load methods from the abstract parent class are strongly typed to the child so that the following line will work as expected:

ApplicationParameters parameters = ApplicationParameters.Load("settings.xml");

或

ApplicationParameters parameters =
    ApplicationSettings.Load<ApplicationParameters>("settings.xml");

取决于您使用的方法。

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