Problem with converting int to string in Linq to e

Question

var items = from c in contacts
            select new ListItem
            {
                Value = c.ContactId, //Cannot implicitly convert type 'int' (ContactId) to 'string' (Value).
                Text = c.Name
            };
var items = from c in contacts
            select new ListItem
            {
                Value = c.ContactId.ToString(), //Throws exception: ToString is not supported in linq to entities.
                Text = c.Name
            };

Is there anyway I can achieve this? Note, that in VB.NET there is no problem use the first snippet it works just great, VB is flexible, im unable to get used to C#'s strictness!!!

Answer 1

var selectList = db.NewsClasses.ToList<NewsClass>().Select(a => new SelectListItem({
    Text = a.ClassName,
    Value = a.ClassId.ToString()
});

Firstly, convert to object, then toString() will be correct.

Answer 2

One more solution:

c.ContactId + ""

Just add empty string and it will be converted to string.

Answer 3

Using MySql, the SqlFunctions.StringConvert didn't work for me. Since I use SelectListItem in 20+ places in my project, I wanted a solution that work without contorting the 20+ LINQ statements. My solution was to sub-class SelectedListItem in order to provide an integer setter, which moves type conversion away from LINQ. Obviously, this solution is difficult to generalize, but was quite helpful for my specific project.

To use, create the following type and use in your LINQ query in place of SelectedListItem and use IntValue in place of Value.

public class BtoSelectedListItem : SelectListItem
{
    public int IntValue
    {
        get { return string.IsNullOrEmpty(Value) ? 0 : int.Parse(Value); }
        set { Value = value.ToString(); }
    }
}