c# - 具有相似体的通用和非通用方法

Question

我有一个方法叫 ExecuteAsyncServiceRequest使用重载，您会注意到这两种方法的主体是相似的。我发现自己想知道有没有更简洁的方法来编写这些方法？具体来说，不必在方法体中重复自己。

提前致谢!

    /// <summary>
    /// Executes an async service request which returns a response of type TResponse
    /// </summary>
    /// <param name="execute">The service request to execute</param>
    /// <param name="success">Callback when the service request is successful</param>
    /// <param name="failure">Callback when the service request fails</param>
    /// <typeparam name="TResponse">Type of the expected ServiceResult returned from the async request</typeparam>
    protected async void ExecuteAsyncServiceRequest<TResponse>(Func<Task<ServiceResult<TResponse>>> execute,
                                                            Action<TResponse> success,
                                                            Action<string> failure)
    {
        ServiceResult<TResponse> result = await execute();

        if (result.ResultCode == ServiceResult.ServiceResultCode.Failed)
            failure(result.FailureDetails);

        success(result.Response);    
    }

    /// <summary>
    /// Executes an async service request
    /// </summary>
    /// <param name="execute">The service request to execute</param>
    /// <param name="success">Callback when the service request is successful</param>
    /// <param name="failure">Callback when the service request fails</param>       
    protected async void ExecuteAsyncServiceRequest(Func<Task<ServiceResult>> execute,
                                                    Action success,
                                                    Action <string> failure)
    {
        ServiceResult result = await execute();

        if (result.ResultCode == ServiceResult.ServiceResultCode.Failed)
            failure(result.FailureDetails);

        success();
    }

Answer 1

不。不幸的是，这是由于 .NET 本身的类型系统的限制 - 特别是，void不是一种类型。

具有更多功能影响的语言(相对于经典的 OOP)往往没有 void 的概念。 ;相反，存在具有单个值的特殊类型(通常称为 unit )。像这样的东西:

public sealed class Unit {
  private Unit() { }
  public static Unit Instance { get; } = new Unit();
}

你可以用你的代码做一些类似的事情，但这取决于你是否值得:

protected async void ExecuteAsyncServiceRequest(Func<Task<ServiceResult>> execute,
                                                Action success,
                                                Action <string> failure) =>
    ExecuteAsyncServiceRequest(
        async () => new ServiceResult<Unit>(await execute(), Unit.Instance),
        _ => success(),
        failure);

这是假设 ServiceResult<T>可以有一个(可能是 internal )构造函数，它接受 ServiceResult作为参数并复制其所有属性，除了从第二个构造函数参数复制的实际“结果”。