如何返回具有通用属性的C#Web服务? [英] How do I return a C# web service that has a generic property?

问题描述

我正在创建一个Web服务，并且希望对返回数据更加优雅，而不是拥有许多消费者需要检查的属性.

I am creating a web service, and want to be a bit more elegant with the return data, instead of having lots of properties that the consumer needs to check.

根据幕后生成的数据，我需要能够返回错误数据或用户期望的数据.

Depending on what data is generated behind the scenes, I need to be able to return error data, or the data the consumer was expecting.

我没有一个大的平面对象，而是在需要时填充属性，并让用户检查成功"标志，我希望将单个属性Data用作错误类的实例，或者成功类的实例.

Instead of having a large flat object, and filling the properties when needed, and letting the user check a 'success' flag, I'd like a single property, Data, to be either an instance of an error class, or an instance of a success class.

这是我想做的事情

class ItemResponse
{
    public bool Success { get; set; }
    public T Data{ get; set; }
}

if( /*acceptance criteria*/ )
{
    ItemResponse<SuccessData> resp = new ItemResponse<SuccessData>();
    resp.Data = new SuccessData();
}
else
{
    ItemResponse<ErrorData> resp = new ItemResponse<ErrorData>();
    resp.Data = new ErrorData();
}

return resp;


public class SuccessData
{

}

public class ErrorData
{

}

然后让web方法返回具有通用属性的对象.

Then have the web method return the object, with the generic property.

这是可能的，如果可以的话，鉴于必须正确键入webmethod返回类型，我该怎么办?

Is this possible, and if so, how would I do it, given that the webmethod return type has to be typed correctly?

推荐答案

泛型是在编译期间添加类型安全性的工具.因此，必须在编译时知道该类的使用者使用的具体类型.如果您创建函数

Generics are a tool for adding type safety during compile time. Consequently, the concrete type used by the consumer of the class must be known at compile time. If you create a function

List<T> myFunction<T>() {...}

...然后在调用它时需要指定T，例如

...then you need to specify T when calling it, e.g.

var myResult = myFunction<int>();

...这使得在编译时知道具体类型. (即使您未指定T(因为可以推断出它)，具体类型在编译时也是 .)

...which makes the concrete type known at compile time. (Even if you don't specify T because it can be infered, the concrete type is also known at compile time.)

但是，您希望在run-time处确定Data的通用类型:如果发生错误，则返回ItemResponse<SuccessData>，否则返回ItemResponse<ErrorData>.那不是泛型的工作原理.

You, however, want the generic type of Data to be determined at run-time: If an error occured, you return an ItemResponse<SuccessData>, otherwise an ItemResponse<ErrorData>. That's just not how generics work.

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