如何创建动态方法？

huangapple
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英文:

How to create Dynamic Method?

问题

  1. 我有一些方法，每个方法都检查相同的一组条件，如果条件都不满足，则返回null值，否则返回不同类的对象。
  2. 有没有办法不必为每个函数都写这些条件，减少代码量？
  4. public A methode1()
  5. {
  6.     if ///something
  7.         return A("xxx")
  8.     else if ///something
  9.         return A("yyy")
  10.     else if ///something
  11.         return A("zzzz")
  12.     else 
  13.         return Error() // 或者返回null
  14. }
  16. public B methode2()
  17. {
  18.     if ///something
  19.         return B("mmmm")
  20.     else if ///something
  21.         return B("nnn")
  22.     else if ///something
  23.         return B("bbbb")
  24.     else
  25.         return Error() // 或者返回null
  26. }
  28. public C methode3()
  29. {
  30.     if ///something
  31.         return C("oooo")
  32.     else if ///something
  33.         return C("ggg")
  34.     else if ///something
  35.         return C("llll")
  36.     else
  37.         return Error() // 或者返回null
  38. }
英文:

I have a number of methods, each of which checks the same set of conditions and returns a null value if none of the conditions are met, otherwise returns an object of different classes.
Is there a way to not have to write all of these terms for each function and use less code?

  1.     public A methode1()
  2.     {
  3.         if ///something
  4.             return A("xxx")
  5.         else if ///something
  6.             return A("yyy")
  7.         else if ///something
  8.             return A("zzzz")
  9.         else 
  10.             return Error() // or return null
  11.     }
  12.     public B methode2()
  13.     {
  14.         if ///something
  15.             return B("mmmm")
  16.         else if ///something
  17.             return B("nnn")
  18.         else if ///something
  19.             return B("bbbb")
  20.         else
  21.             return Error() // or return null
  22.     }
  24.     public C methode3()
  25.     {
  26.         if ///something
  27.             return C("oooo")
  28.         else if ///something
  29.             return C("ggg")
  30.         else if ///something
  31.             return C("llll")
  32.         else
  33.             return Error() // or return null
  34.     }

答案1

得分: 1

标准方法是，您可以使用带有接口/抽象类的工厂类。

  1. public interface IOutput {
  2. }
  3. public class Output1 : IOutput{
  4. }
  5. public class Output2 : IOutput{
  6. }
  7. public class MyFactory
  8. {
  9.     public IOutput Get()// 添加任何参数列表
  10.     {
  11.        if(条件) // 如果必要，可以在条件中使用参数
  12.            return new Output1();
  13.        else
  14.            return new Output2();
  15.     }
  16. }
英文:

Standard approch is , you can use a factory class with interface/abstract class

  1. public interface IOutput {
  2. }
  3. public class Output1 : IOutput{
  4. }
  5. public class Output2 : IOutput{
  6. }
  7. public class MyFactory
  8. {
  9.     public IOutput Get()// add args list of any
  10.     {
  11.        if(condition) // you can use args in condition if necessary
  12.            return new Output1();
  13.        else
  14.            return new Output2();
  15.     }
  16. }

答案2

得分: 1

你可以将模板方法模式与泛型结合使用：

  1. public abstract class AbstractTemplate<T>
  2. {
  3.     public T Method()
  4.     {
  5.         if ///something
  6.             return Do1();
  7.         else if ///something
  8.             return Do2();
  9.         else if ///something
  10.             return Do3();
  11.         else 
  12.             return Error(); // 或者返回 null
  13.     }
  14.     protected abstract T Do1();
  15.     protected abstract T Do2();
  16.     protected abstract T Do3();
  17. }
  19. public class ConcreteATemplate : AbstractTemplate<A>
  20. {
  21.     protected override A Do1() => A("xxx");
  22.     protected override A Do2() => A("yyy");
  23.     protected override A Do3() => A("zzzz");
  24. }
  26. 然后在你的方法中使用它：
  28. ```csharp
  29. public A Method1() => new ConcreteATemplate().Method(); // 也可以在你的情况下“缓存”实例在静态 readonly 字段中。
  31. [1]: https://en.wikipedia.org/wiki/Template_method_pattern
  32. [2]: https://learn.microsoft.com/en-us/dotnet/csharp/programming-guide/generics/
英文:

You can combine template method pattern with generics:

  1. public abstract class AbstractTemplate&lt;T&gt;
  2. {
  3.     public T methode()
  4.     {
  5.         if ///something
  6.             return Do1();
  7.         else if ///something
  8.             return Do2();
  9.         else if ///something
  10.             return Do3();
  11.         else 
  12.             return Error() // or return null
  13.     }
  14.     protected abstract T Do1();
  15.     protected abstract T Do2();
  16.     protected abstract T Do3();
  17. }
  19. public class ConcreteATemplate : AbstractTemplate&lt;A&gt;
  20. {
  21.     protected override T Do1() =&gt; A(&quot;xxx&quot;);
  22.     protected override T Do2() =&gt; A(&quot;yyy&quot;);
  23.     protected override T Do3() =&gt; A(&quot;zzzz&quot;);
  24. }

And use it inside your methods:

  1. public A methode1() =&gt; new ConcreteATemplate().methode(); // also can &quot;cache&quot; instance in your case in static readonly field.

答案3

得分: 0

你可以使用具有通用类型参数和一组初始值的方法。

  1. private T GetIfOkay<T>(string a, string b, string c)
  2.     where T : new()
  3. {
  4.     if (something)
  5.         return new T(a);
  6.     else if (something else)
  7.         return new T(b);
  8.     else if (yet something else)
  9.         return new T(c);
  10.     else
  11.         return null;
  12. }
  14. public A methode1()
  15. {
  16.     return GetIfOkay<A>("xxx", "yyy", "zzzz");
  17. }
  19. public B methode2()
  20. {
  21.     return GetIfOkay<B>("mmmm", "nnn", "bbbb");
  22. }
  24. // etc.

如果需要更动态的行为，可以参考 @donggas90 的解决方案。

参见：

英文:

You could use a method with a generic type parameter and a set of initial values.

  1. private T GetIfOkay&lt;T&gt;(string a, string b, string c)
  2.     where T : new()
  3. {
  4.     if (something)
  5.         return new T(a);
  6.     else if (something else)
  7.         return new T(b);
  8.     else if (yet something else)
  9.         return new T(c);
  10.     else
  11.         return null;
  12. }
  14. public A methode1()
  15. {
  16.     return GetIfOkay&lt;A&gt;(&quot;xxx&quot;, &quot;yyy&quot;, &quot;zzzz&quot;);
  17. }
  19. public B methode2()
  20. {
  21.     return GetIfOkay&lt;B&gt;(&quot;mmmm&quot;, &quot;nnn&quot;, &quot;bbbb&quot;);
  22. }
  24. // etc.

If you need a more dynamic behaviour, @donggas90's solution.

See:

答案4

得分: 0

你可以使用通用方法和仓储模式。以下是一个使用C#的通用方法示例，我认为它可能会给你一些想法：

  1. public static async Task<List<ObjectType>> GetDataList<ObjectType>(UserAuthorization token) where ObjectType : BaseModel
  2. {
  3.     List<ObjectType> data = new List<ObjectType>();
  4.     try
  5.     {
  6.         if (token.UserTypes.Count > 0)
  7.         {
  8.             Type genericClass = typeof(Repository<>);
  9.             Type constructedClass = genericClass.MakeGenericType(typeof(ObjectType));
  10.             MERPDbContext mERPContext = new MERPDbContext();
  11.             var created = (Repository<ObjectType>)Activator.CreateInstance(constructedClass, mERPContext);
  12.             if (token.UserTypes[0].Id == (byte)UserTypes.SuperAdmin)
  13.             {
  14.                 var sub = await created.GetAsync();
  15.                 data = sub.ToList();
  16.             }
  17.             else if (token.UserTypes[0].Id == (byte)UserTypes.InstituteAdmin)
  18.             {
  19.                 data = await created.FilterListAsync(x => x.InstituteId == token.InstituteID);
  20.             }
  21.             else
  22.             {
  23.                 data = await created.FilterListAsync(x =>
  24.                     x.InstituteId == token.InstituteID && x.CampusId == token.CampusID);
  25.             }
  26.         }
  27.     }
  28.     catch (Exception e)
  29.     {
  31.     }
  32.     return data;
  33. }

请注意，这是提供给你的通用方法示例，具体的实现可能需要根据你的应用程序需求进行调整。

英文:

You can use generic method and repository pattern. Here is a generic method example with C#. I think it may give you some idea..

  1. public static async Task&lt;List&lt;ObjectType&gt;&gt; GetDataList&lt;ObjectType&gt;(UserAuthorization token) where ObjectType : BaseModel
  2.         {
  3.             List&lt;ObjectType&gt; data = new List&lt;ObjectType&gt;();
  4.             try
  5.             {
  6.                 if(token.UserTypes.Count &gt; 0)
  7.                 {
  8.                     Type genericClass = typeof(Repository&lt;&gt;);
  9.                     Type constructedClass = genericClass.MakeGenericType(typeof(ObjectType));
  10.                     MERPDbContext mERPContext = new MERPDbContext();
  11.                     var created = (Repository&lt;ObjectType&gt;)Activator.CreateInstance(constructedClass, mERPContext);
  12.                     if (token.UserTypes[0].Id == (byte)UserTypes.SuperAdmin)
  13.                     {
  14.                         var sub = await created.GetAsync();
  15.                         data = sub.ToList();
  16.                     }
  17.                     else if (token.UserTypes[0].Id == (byte)UserTypes.InstituteAdmin)
  18.                     {
  19.                         data = await created.FilterListAsync
  20.                                             (x =&gt; x.InstituteId == token.InstituteID);
  21.                     }
  22.                     else
  23.                     {
  24.                         data = await created.FilterListAsync(x =&gt;
  25.                                             x.InstituteId == token.InstituteID &amp;&amp; x.CampusId == token.CampusID);
  26.                     }
  27.                 }
  28.             }
  29.             catch (Exception e)
  30.             {
  31.                 
  32.             }
  33.             return data;
  34.         }

答案5

得分: 0

根据您的评论，我尝试重新编写您的示例，希望这能帮助您。如果需要更多明确信息，请随时提问。

  1. class Program
  2. {
  3.     static void Main(string[] args)
  4.     {
  5.         var objFactory = new MyFactory();
  6.         // 获取并强制转换返回对象
  7.         A a1 = (A)objFactory.ConsolidatedMethod("Condition 1 for Objct A", "xxx");
  9.         // 或直接分配给基础对象
  10.         IOutput a2 = objFactory.ConsolidatedMethod("Condition 2 for Objct A", "yyyy");
  12.         // 使用匿名对象
  13.         var b1 = objFactory.ConsolidatedMethod("Condition 1 for Objct B", "mmmm");
  15.         var nullcheck1 = objFactory.ConsolidatedMethod("null conditionj", "i'm null");
  16.     }
  17. }
  19. interface IOutput
  20. {
  21. }
  23. class A : IOutput
  24. {
  25.     public A(string objParam)
  26.     {
  27.     }
  28. }
  30. class B : IOutput
  31. {
  32.     public B(string objParam)
  33.     {
  34.     }
  35. }
  37. class NullOutput : IOutput
  38. {
  39.     public NullOutput(string objParam)
  40.     {
  41.     }
  42. }
  44. class MyFactory
  45. {
  46.     /// <summary>
  47.     /// 演示
  48.     /// </summary>
  49.     /// <param name="arg">根据您的需求使用此参数</param>
  50.     /// <param name="objparam">根据您的需求使用此参数</param>
  51.     /// <returns>IOutput</returns>
  52.     public IOutput ConsolidatedMethod(string arg, string objparam)
  53.     {
  54.         IOutput _output = default;
  56.         if (arg == "Condition 1 for Objct A")
  57.             _output = new A(objparam);
  58.         else if (arg == "Condition 2 for Objct A")
  59.             _output = new A(objparam);
  60.         else if (arg == "Condition 1 for Objct B")
  61.             _output = new B(objparam);
  62.         else if (arg == "Condition 2 for Objct B")
  63.             _output = new B(objparam);
  64.         else
  65.             _output = new NullOutput(objparam);
  67.         return _output;
  68.     }
  69. }
英文:

According to your comment, I tried to rewrite your sample, hope this will help you. ask freely if you need more clarity.

  1. class Program
  2. {
  3.     static void Main(string[] args)
  4.     {
  5.         var objFactory = new MyFactory();
  6.         // Get and cast return object
  7.         A a1= (A) objFactory.ConsolidatedMethod(&quot;Condition 1 for Objct A&quot;, &quot;xxx&quot;);
  9.         // Or Directly assian to base object
  10.         IOutput a2 = objFactory.ConsolidatedMethod(&quot;Condition 2 for Objct A&quot;, &quot;yyyy&quot;);
  12.         // use anonymous object
  13.         var b1= objFactory.ConsolidatedMethod(&quot;Condition 1 for Objct B&quot;, &quot;mmmm&quot;);
  15.         var nullcheck1 = objFactory.ConsolidatedMethod(&quot;null conditionj&quot;, &quot;i&#39;m null&quot;);
  16.     }
  17. }
  19. interface IOutput
  20. {
  21. }
  23. class A : IOutput
  24. {
  25.     public A(string objParam)
  26.     {
  27.     }
  28. }
  30. class B : IOutput
  31. {
  32.     public B(string objParam)
  33.     {
  34.     }
  35. }
  37. class NullOutput : IOutput
  38. {
  39.     public NullOutput(string objParam)
  40.     {
  41.     }
  42. }
  44. class MyFactory
  45. {
  46.     /// &lt;summary&gt;
  47.     /// Demo 
  48.     /// &lt;/summary&gt;
  49.     /// &lt;param name=&quot;arg&quot;&gt;you can use this based on your requirement &lt;/param&gt;
  50.     /// &lt;param name=&quot;objparam&quot;&gt;you can use this based on your requirement &lt;/param&gt;
  51.     /// &lt;returns&gt;IOutput&lt;/returns&gt;
  52.     public IOutput ConsolidatedMethod(string arg, string objparam)
  53.     {
  54.         IOutput _output=default;
  56.         if (arg == &quot;Condition 1 for Objct A&quot;)
  57.             _output = new A(objparam);
  58.         else if (arg == &quot;Condition 2 for Objct A&quot;)
  59.             _output = new A(objparam);
  60.         else if (arg == &quot;Condition 1 for Objct b&quot;)
  61.             _output = new B(objparam);
  62.         else if (arg == &quot;Condition 2 for Objct B&quot;)
  63.             _output = new B(objparam);
  64.         else
  65.             _output = new NullOutput(objparam);
  67.         return _output;
  68.     }
  69. }

huangapple
  • 本文由 发表于 2020年8月11日 23:07:26
  • 转载请务必保留本文链接：https://go.coder-hub.com/63361066.html
  • c#
  • function
  • java
  • methods
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