返回实体框架中的“计算”字段

Question

I have this piece of code. My intention is to create field, which I can pass as textValue to SelectList object.

Here are my two entities:

public class Ski
{
    public int ID { get; set; }
    public int BrandID { get; set; }

    public virtual Brand Brand { get; set; }

    [NotMapped]
    public string BrandName
    {
        get
        {
            return this.Brand.Name.ToString();
        }
    }

}

public enum BrandName
{
    Blizzard, MCAD, ATOMIC
}

public class Brand
{
    public int ID { get; set; }
    public BrandName Name { get; set; }
}

And SelectList initialization

ViewBag.SkiID = new SelectList(db.Skis, "ID", "BrandName");

But such a solution does not seem to work.

How can such a thing be implemented then?

Error says that I have an associated DataReader.

Answer 1

Create this view model:

public class SkiViewModel
{
    public string Text{ get; set; }
    public int Value{ get; set; }
}

and change your code:

var result = db.Skis.Select(x => new SkiViewModel()
{
    Text = x.BrandName.Name ,
    Value = ID

});

ViewBag.Skis = new SelectList(result, "Value", "Text");

and in view:

@Html.DropDownList("Value", new SelectListItem(ViewBag.Skis , "Value", "Text"))