EmployeeTracker/InvestTracker/Models/TitleList.cs

using System.Collections.ObjectModel;
using InvestTracker.Entities;
using System.Collections.Generic;
using Microsoft.EntityFrameworkCore;
using System.Linq;

namespace InvestTracker.Models
{
    class TitleList : ObservableCollection<Title>
    {
        public TitleList() 
        {
            var dbContext = new InvestContext();
            List<Title> allTitles = dbContext.Titles.Select(t => t).ToList();
            this.AddRange(allTitles);
        }
    }
}