Question

我试图在循环中将对象列表分配给相同类型的Property但我无法分配它。

它始终为null。

public IEnumerable<AppointmentModel> AddProducts (IEnumerable<AppointmentModel> apps)
{
    foreach(var app in apps)
    {
        var products = new List<ProductsEntity>
        {
            new ProductsEntity {Id = "A", Desc = "ABC"},
            new ProductsEntity {Id = "B", Desc = "ABC"},
            new ProductsEntity {Id = "C", Desc = "ABC"}
        }
        app.Products = products; // Values are successfully getting assigned here
    }
    return apps; //apps.FirstOrDefault().Products is Null here
}

public class AppointmentModel
{
    public int Id {get;set;}
    public IEnumerable<ProductEntity> Products {get;set;}
}

我已尝试将我的应用转换为IQueryable和IList，但它仅为null

Answer 1

您已在foreach循环中枚举apps变量。在循环之后，您尝试访问它的第一个元素，但枚举器已经到达列表的末尾。

如果你把它的元素作为一个数组，你将不会遇到这样的问题。

试试这个。

    public IEnumerable<AppointmentModel> AddProducts(IEnumerable<AppointmentModel> apps)
    {
        var appointmentModels = apps as AppointmentModel[] ?? apps.ToArray();
        foreach (var app in appointmentModels)
        {
            var products = new List<ProductsEntity>
            {
                new ProductsEntity {Id = "A", Desc = "ABC"},
                new ProductsEntity {Id = "B", Desc = "ABC"},
                new ProductsEntity {Id = "C", Desc = "ABC"}
            };
            app.Products = products; // Values are successfully getting assigned here
        }
        return appointmentModels; //apps.FirstOrDefault().Products is Null here
    }

无法将List分配给IEnumerable对象

1 个答案: