继承的C＃类失去“参考”

Question

我有一个使用接口的部分类，因为我无法继承原始抽象类，因为其他部分类是从Entity Framework 4自动生成的，因此已经继承了ObjectContext。

我的部分课程有以下内容：

namespace Model
{
    using Microsoft.Practices.EnterpriseLibrary.Validation;
    using Microsoft.Practices.EnterpriseLibrary.Validation.Validators;
    using Utilities.BusinessRules;
    using Utilities.BusinessRules.Rules;

    [HasSelfValidation]
    public partial class MyObject : IBusinessObject
    {
        private readonly IBusinessObject businessObject = new BusinessObject();

        private IBusinessObject BusinessObject
        {
            get
            {
                return businessObject;
            }
        }

        public Comment()
        {
            AddRule(new ValidateRequired("Title"));
        }

        public void AddRule(BusinessRule rule)
        {
            BusinessObject.AddRule(rule);
        }

        [SelfValidation]
        public void Validate(ValidationResults results)
        {
            BusinessObject.Validate(results);
        }
    }
}

这是界面：

namespace Utilities.BusinessRules
{
    using Microsoft.Practices.EnterpriseLibrary.Validation;

    public interface IBusinessObject
    {
        void AddRule(BusinessRule rule);

        void Validate(ValidationResults results);
    }
}

并实施：

namespace Utilities.BusinessRules
{
    using System.Collections.Generic;
    using System.Linq;
    using Microsoft.Practices.EnterpriseLibrary.Validation;
    using Microsoft.Practices.EnterpriseLibrary.Validation.Validators;

    public class BusinessObject : IBusinessObject
    {
        private readonly IList<BusinessRule> businessRules = new List<BusinessRule>();

        public void AddRule(BusinessRule rule)
        {
            this.businessRules.Add(rule);
        }

        [SelfValidation]
        public void Validate(ValidationResults results)
        {
            foreach (var rule in this.businessRules)
            {
                if (!rule.Validate(this))
                {
                     results.AddResult(new ValidationResult(rule.ErrorMessage, this, rule.Key, rule.Tag, null));
                }
            }
        }
    }
}

不要担心规则，他们的工作。 问题是如果我在测试项目中使用抽象类，那么BusinessObject中的Validate（）方法将正确地标识（this）为继承抽象类的任何类（在此示例中，我希望它是MyObject）。 不幸的是，切换到接口，（这）丢失了继承类，而是将其标识为BusinessObject。

我怎样才能使继承类正确识别？

这是调用控制台类：

namespace ModelConsumer
{
    using Model;
    using System;
    using Microsoft.Practices.EnterpriseLibrary.Validation;

    class Program
    {
        static void Main(string[] args)
        {
            using (var myEntities = new MyEntities())
            {
                var myObject= new MyObject();

                myObject.Title = "Credo";

                var validationResults = Validation.Validate(myObject);

                if (validationResults.IsValid)
                {
                    myEntities.MyObjects.AddObject(myObject);
                    //myEntities.SaveChanges();

                    Console.WriteLine("Valid.");
                }
                else
                {
                    foreach (var validationResult in validationResults)
                    {
                        Console.WriteLine(validationResult.Message);
                    }
                }

                Console.Read();
            }
        }
    }
}

这应该是有效的，但是将无效，因为（this）被标识为类型BusinessObject而不是MyObject。

哎呀！ 我很亲密，这很令人烦恼。

理查德

Answer 1

我相信您的BusinessObject实现是在假设它将被继承的情况下编写的。 但是，现在您将其用作组合对象，您需要进行一些更改：

public interface IBusinessObjectValidator
{
  void AddRule(BusinessRule rule);

  void Validate(IBusinessObject target, ValidationResults results);
}


Public class BusinessObject: IBusinessObjectValidator
{
...

  public void Validate(IBusinssObject target, ValidationResults results)
  {
      foreach (var rule in this.businessRules)
      {
          if (!rule.Validate(target))
          {
             results.AddResult(new ValidationResult(rule.ErrorMessage, target, rule.Key, rule.Tag, null));
          }
      }
  }
}

您将按如下方式使用它：

[HasSelfValidation]
    public partial class MyObject : IBusinessObject
    {
        private readonly IBusinessObjectValidator validator = new BusinessObject();

        private IBusinessObjectValidator BusinessObjectValidator
        {
            get
            {
                return validator ;
            }
        }
    public Comment()
    {
        AddRule(new ValidateRequired("Title"));
    }

    public void AddRule(BusinessRule rule)
    {
        validator .AddRule(rule);
    }

    [SelfValidation]
    public void Validate(ValidationResults results)
    {
        validator.Validate(this, results);
    }
}

基本上，我们说我们将在外部实现验证器，因此，我们需要将目标对象（正在验证）传递给validate方法。 我还建议将BusinessObject重命名为BusinessObjectValidtor。