InvalidOperationException: Sequence contains no elements

Question

I have written a code in .net using mvc and entity framework:

@{
   List<DAL.Project> oldProjectList = new BL.ProjectLogic().getProjects(userName).Where(s => s.Status == "Not Active").ToList();
}
@foreach (DAL.Project p in oldProjectList)
{
     {some code}
}

The first line of code should return a list of "Not Active" projects, and it actually works. but it only works on users that have "Non Active" projects, other users get an exception in the foreach line saying:

[InvalidOperationException: Sequence contains no elements]

How to fix it? Thanks

Answer 1

Are you sure that the exception is being thrown in your foreach? In this small reproducible example, I can't get the same error while executing:

using System;
using System.Collections.Generic;
using System.Linq;

namespace LinqPlayground
{
    class Program
    {
        public class Project
        {
            public string Status { get; set; }
        }

        static void Main(string[] args)
        {
            var projects = GetProjects("test").Where(project => project.Status == "Not Active").ToList();
            foreach (var project in projects)
            {
                Console.WriteLine(project.Status);
            }
        }

        public static IEnumerable<Project> GetProjects(string userName)
        {
            return new List<Project>();
        }
    }
}

Answer 2

Use the first part of that line, but not the ToList().

Instead, save the result of the Where() in a var, and then check that VAR using. Any():

var temp = new BL.Proje s ctLogic().getProjects(userName)
    .Where( => s.Status == "Not Active");

List<DAL.Project> oldProjectList = 
    temp.Any() ? 
        temp.ToList() : 
        new List<DAL.Project>() ;