c# – 实现具有类型约束的通用接口

我有一个Visual Studio 2008 C#2.0 CF项目,我正在实现一个通用接口IComparison.可以调用IComparison.Compare方法来执行对指定对象有效的任何类型的比较,因此我不想对其设置类型约束.

public interface IComparison<EXPECTED_ParaM>
{
    Result Compare<RETURNED_ParaM>(RETURNED_ParaM returned);
}

但是,实施可以更具体.在这种情况下,我想说可以将给予GreaterThan.Compare的参数与构造函数中通过System.IComparable给出的EXPECTED_ParaM进行比较.

public class GreaterThan<EXPECTED_ParaM> : IComparison<EXPECTED_ParaM>
{
    private EXPECTED_ParaM expected_;

    public GreaterThan(EXPECTED_ParaM expected)
    {
        expected_ = expected;
    }

    public Result Compare<RETURNED_ParaM>(RETURNED_ParaM returned) 
        where RETURNED_ParaM : IComparable< EXPECTED_ParaM >
    {
        return ((returned == null && expected_ == null) ||
                (returned != null && returned.Compareto( expected_ ) > 0)) ?
               Result.Fail : Result.Pass;
    }
}

不幸的是,这给了我错误：

error CS0460: Constraints for override and explicit interface implementation methods are inherited from the base method,so they cannot be specified directly

为了能够使用RETURNED_ParaM对象执行EXPECTED_ParaM对象的任意比较,我需要做什么？

谢谢,
PaulH

解决方法

这个怎么样？

public interface IComparison<EXPECTED_ParaM,RETURNED_ParaM>
{
    Result Compare(RETURNED_ParaM returned);
}

public class GreaterThan<EXPECTED_ParaM,RETURNED_ParaM> : IComparison<EXPECTED_ParaM,RETURNED_ParaM> where RETURNED_ParaM : IComparable<EXPECTED_ParaM>
{
    private EXPECTED_ParaM expected_;      
    public GreaterThan(EXPECTED_ParaM expected)     
    {         expected_ = expected;     }      

    public Result Compare(RETURNED_ParaM returned)          
    {
        return ((returned == null && expected_ == null) || 
            (returned != null && returned.Compareto( expected_ ) > 0)) ?                
            Result.Fail : Result.Pass;
    }
}