c# - 隐式转换数组

Question

我有两个 atm 相同且定义了类型转换的类:

 public static implicit operator SponsoredBrandViewModel(SponsoredBrand sponsoredBrand)
        =>
            new SponsoredBrandViewModel
            {
                Id = sponsoredBrand.Id,
                BrandId = sponsoredBrand.RelatedEntityId,
                To = sponsoredBrand.To,
                From = sponsoredBrand.From,
                Importance = sponsoredBrand.Importance
            };
    public static implicit operator SponsoredBrand(SponsoredBrandViewModel sponsoredBrandViewModel)
        =>
            new SponsoredBrand
            {
                Id = sponsoredBrandViewModel.Id,
                RelatedEntityId = sponsoredBrandViewModel.BrandId,
                To = sponsoredBrandViewModel.To,
                From = sponsoredBrandViewModel.From,
                Importance = sponsoredBrandViewModel.Importance
            };

我想在它是数组时进行转换。

ar dbSponsoredBrands = await this._sponsoredBrandRepository.GetAsync();
            var viewModels = (IEnumerable<SponsoredBrandViewModel>) dbSponsoredBrands.ToEnumerable();

但是这会抛出 invalidcast 异常。

有什么想法吗？

Answer 1

您正在尝试转换集合对象 IEnumerable<SponsoredBrand>进入 IEnumerable<SponsoredBrandViewModel>您在其中为实际对象定义了隐式转换运算符。您需要遍历集合并创建一个新集合，例如

var dbSponsoredBrands = await this._sponsoredBrandRepository.GetAsync();
var viewModels = dbSponsoredBrands.Select(x => (SponsoredBrandViewModel)x);