Linq-to-sql 错误：“int[]”不包含“包含”的定义

Question

I am having an error:

Error 2 'int[]' does not contain a definition for 'Contains' and the best extension method overload 'System.Linq.Enumerable.Contains(System.Collections.Generic.IEnumerable, TSource)' has some invalid arguments

This is my code:

public partial class mymymy : System.Web.UI.Page
{
    int[] validType = { 2, 3, 4, 5, 6, 8, 13, 14, 16, 22 };

    protected void Page_Load(object sender, EventArgs e)
    {
    }

    protected void LinqDataSource_Selecting(object sender, LinqDataSourceSelectEventArgs e)
    {
        using (var dc = new soxMainDataContext())
        {
            var qry = from item in dc.LeaveRequests
                  where **validType**.Contains(item.Type)
                      && item.MgtApproval == null
                  select item;
            e.Result = qry;
        }
    }
}

Answer 1

I strongly suspect that item.Type isn't an int . Is it an enum? If so, try explicitly casting:

var qry = from item in dc.LeaveRequests
          where validType.Contains((int) item.Type)
                && item.MgtApproval == null
          select item;

Alternatively, as dot notation:

var query = dc.LeaveRequests.Where(item => validType.Contains((int) item.Type)
                                           && item.MgtApproval == null);

Answer 2

item.Type不是int 。

Answer 3

var consulta = from pr in lsprodcts 
               where pr.nProductoID.ToString().Contains(Idproducto.ToString())
               select new
               {
                   pr.nProductoID,
                   ProdName = pr.cNombre,
                   pr.cDescripcion,
               };

`

Answer 4

Don't forget to import Linq with using System.Linq; at the very top of the class.