如何确定如果对象是其基本泛型类型？ [英] How to Identify If Object Is Of A Base Generic Type?

问题描述

我有一个类

DataMapper<TDalType, TFieldType> : DataMapperBase

有关具体的实体，我有一个

For a particular entity, I have a

ObjectADataMapper<TFieldType> : DataMapper<ObjectADal, TFieldType>

然后我有一个DataMapperBase的实例，并需要确定它是否是一个版本的实体ObjectADataMapper（有TFieldType的任意值）。

I then have an instance of a DataMapperBase and need to determine if it is an entity that is a version of ObjectADataMapper (with any value of TFieldType).

推荐答案

如果对象的类型是通用的，如果你可以看到检查此相应的通用模板是您正在寻找的通用模板。例如：

You can check this by seeing if the object's type is generic and if the corresponding generic template is the generic template that you are looking for. For example:

var type = obj.GetType();
bool isObjectADataMapper = type.IsGenericType && type.GetGenericTypeDefinition() == typeof(ObjectADataMapper<>);

或者，在一个可重用的方式

Or, in a reusable way

  bool IsInstanceOfGenericTypeClosingTemplate(object obj, Type genericTypeDefinition){ 
      if(obj == null) throw new ArgumentNullException("obj");
      if(genericTypeDefinition== null) throw new ArgumentNullException("genericTypeDefinition");
      if(!genericTypeDefinition.IsGenericTypeDefinition) throw new ArgumentException("Must be a generic type definition.", "genericTypeDefinition");
      Type type = obj.GetType(); 
      return type.IsGenericType && type.GetGenericTypeDefinition() == genericTypeDefinition;
  }

您甚至可以借此进一步，看看类型由通用派生问题类型定义。例如，假设你有：

You could even take this further and see if the type is derived from the generic type definition in question. For example, consider that you have:

  public class StringDataMapper : ObjectADataMapper<string>
  { 
     // .... whatever
  }

在这种情况下，我提供的方法将失败。所以，你必须做这样的事情。

In this case the method I provided would fail. So you'd have to do something like

  bool IsInstanceOfGenericTypeClosingTemplateOrSubclassThereof(object obj, Type genericTypeDefinition){ 
      if(obj == null) throw new ArgumentNullException("obj");
      if(genericTypeDefinition== null) throw new ArgumentNullException("genericTypeDefinition");
      if(!genericTypeDefinition.IsGenericTypeDefinition) throw new ArgumentException("Must be a generic type definition.", "genericTypeDefinition");

      Type type = obj.GetType();
      while ( type != typeof(object) )
      {
         if(type.IsGenericType && type.GetGenericTypeDefinition() == genericTypeDefinition) 
         {
            return true;
         }
         type = type.BaseType;
      } 
      return false;
  }

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