c# - LINQ to Entities 仅支持无参数构造函数和初始值设定项

Question

我不想每次都初始化每个字段，我想在构造函数中初始化所有initsilizirovat，可以吗？

 var districts = _districtRepository.FindBy(d => d.CityID == id).Select(d => new DistrictViewModel(d)).ToList();

模型:

public class DistrictViewModel
{
    public Int32 ID { get; set; }
    public String Name { get; set; }

    public DistrictViewModel()
    {

    }

    public DistrictViewModel(District district)
    {
        if (district != null)
        {
            ID = district.ID;
            Name = district.Name;
        }
    }
}

Answer 1

你可以这样做:

var districts = _districtRepository.FindBy(d => d.CityID == id)
                                   .AsEnumerable()
                                   .Select(d => new DistrictViewModel(d))
                                   .ToList();

在这种情况下，您的语句 .Select(d => new DistrictViewModel(d)) 是 linq-to-object 语句，而不是 linq-to-entity，它会起作用。