通用接口
这是我的代码
public interface ITranslator<E, R>
{
E ToEntity<T>(R record);
}
class Gens : ITranslator<string, int>
{
#region ITranslator<string,int> Members
public string ToEntity<MyOtherClass>(int record)
{
return record.ToString();
}
#endregion
}
当我编译它时，我得到一个错误类型参数声明必须是标识符而不是类型
为什么我不能有ToEntity但只能有 ToEntity ??
编辑：MyOtherClass 在做什么？我正在实体（相当于实体框架的 POCO）和记录（框架返回的对象）之间转换多个表/类。所以我想用它来进行我的班级特定转换
Here is my code
public interface ITranslator<E, R>
{
E ToEntity<T>(R record);
}
class Gens : ITranslator<string, int>
{
#region ITranslator<string,int> Members
public string ToEntity<MyOtherClass>(int record)
{
return record.ToString();
}
#endregion
}
When I compile this, I get an error Type parameter declaration must be an identifier not a type
Why is that I cannot have ToEntity<MyOtherClass> but can only have ToEntity<T> ??
Edit: what is MyOtherClass doing ? I am converting between entities(POCOs equivalent of Entity framework) and record(Object returned by the framework) for multiple tables/classes. So I would want to use this to do my class specific conversion
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评论（3）
您的接口有一个通用
ToEntity方法，您已在实现类Gens中将其设为非通用方法ToEntity。 （泛型方法可以采用任何类型参数，可能会对T给予一定的限制。您的Gens类正在尝试为提供定义>ToEntity仅适用于类型参数MyOtherClass，这违背了泛型的目的。）在您的代码示例中，尚不清楚您的
Gens 类正在尝试使用MyOtherClass类型；它当然不涉及ToEntity的逻辑。我们需要更多信息才能进一步指导您。为了说明这一点，以下是您当前对
ITranslator界面提供的简单英语定义：另一方面，您的
Gens类按照当前的设计方式“实现”了上述接口，如下所示：从这两个描述中，很明显
Gens类并没有真正执行ITranslator接口所保证的<也就是说，它不愿意接受用户为其ToEntity方法指定的类型，这就是无法为您编译此代码的原因。Your interface has a generic
ToEntity<T>method that you've made non-generic in your implementation classGensasToEntity<MyOtherClass>. (A generic method could take any type parameter, possibly given certain constraints onT. YourGensclass is trying to provide a definition forToEntityonly for the type parameterMyOtherClass, which defeats the purpose of generics.)In your code example, it's unclear how your
Gensclass is trying to use theMyOtherClasstype; it's certainly not involved in the logic ofToEntity. We'd need more information to be able to guide you further.To illustrate, here's what your current definition of the
ITranslator<E, R>interface offers, in plain English:Your
Gensclass, on the other hand, the way it's currently designed, "implements" the above interface like so:From these two descriptions, it's clear that the
Gensclass is not really doing what theITranslator<E, R>interface guarantees. Namely, it is not willing to accept a user-specified type for itsToEntitymethod. That's why this code won't compile for you.您必须声明对泛型类型的约束。
You must declare a constraint on a generic type.
这对我来说在 LINQpad 中编译没问题。也许你在某处有一个名为 E、R 或 T 的类型？啊，我明白你想要做什么...你在某处将 MyOtherClass 定义为类，但你试图将它用作类型ToEntity 中的参数。您究竟希望 MyOtherClass 如何参与 ToEntity？
That compiles OK for me in LINQpad. Maybe you have a type named E, R, or T somewhere?Ahh I see what you're trying to do... you have MyOtherClass defined as a class somewhere yet you're trying to use it as a type argument in ToEntity. How exactly do you want MyOtherClass involved in ToEntity?