转换IList <int> 到IList <string>

Question

code in my EFService:

    private IDbSet<Item> _Items;
    private int _SearchTakeCount = 10;
    public IList<string> SearchByArticleCount(int articleCount)
        {
            return _Items.AsNoTracking().Where(m => m.Articles.Count().Equals(articleCount))
                .Take(_SearchTakeCount)
                .Select(m => m.Articles.Count().ToString())
                .Distinct()
                .ToList();
        }

code in my Controller:

public virtual ActionResult AutoCompleteSearch(string term, KeywordSearchBy searchBy = KeywordSearchBy.Name)
        {
            IList<string> data = new List<string>();
        switch (searchBy)
        {
            case ItemSearchBy.Name:
                data = _ItemService.SearchByName(term);
                break;
            case ItemSearchBy.ArticleCount:
                int articleCount = Convert.ToInt32(term);
                data = _ItemService.SearchByArticleCount(articleCount);
                break;
        }

when I run the project the exception is accured. this exception is: LINQ to Entities does not recognize the method 'System.String ToString()' method, and this method cannot be translated into a store expression.

Answer 1

Make ToString() call as LINQ to Objects query, after EF part is done:

public IList<string> SearchByArticleCount(int articleCount)
{
    return _Items.AsNoTracking().Where(m => m.Articles.Count().Equals(articleCount))
        .Take(_SearchTakeCount)
        .Select(m => m.Articles.Count())
        .Distinct()
        .AsEnumerable()
        .Select(x => x.ToString())
        .ToList();
}