c# - 使用 MOQ 模拟异步 Get 方法

Question

如何摆脱此错误消息:

Error   5   Cannot implicitly convert type 'System.Threading.Tasks.Task<System.Collections.Generic.IEnumerable<TGB.Business.DTO.SchoolyearDTO>>' to 'System.Collections.Generic.IEnumerable<TGB.Business.DTO.SchoolyearDTO>'. An explicit conversion exists (are you missing a cast?)   

我以为我的 Task.FromResult 会解决这个问题，但没有......

mockService.Setup<IEnumerable<SchoolyearDTO>>(c => c.GetSchoolyears()).Returns(
                    Task.FromResult(Enumerable.Empty<SchoolyearDTO>()));

public async Task<IEnumerable<SchoolyearDTO>> GetSchoolyearsAsync()
{
    var schoolyears = await ...
}

Answer 1

GetSchoolyearsAsync是一个异步方法，所以它返回一个 Task<IEnumerable<SchoolyearDTO>>而不仅仅是 IEnumerable<SchoolyearDTO> .您需要在 SetupGet 的类型参数中指定

mockService.SetupGet<Task<IEnumerable<SchoolyearDTO>>>(c => c.GetSchoolyears()).
    Returns(Task.FromResult(Enumerable.Empty<SchoolyearDTO>()));