title: C# How to return a specific column from a database table using SQL
body: <p>I have a database with a table <code>person</code> that has columns <code>PersonID, firstName, lastName</code>.</p>
  
  <p>I am trying to fill a combobox with all the first names from this table. This is what I have so far:</p>
  
  <pre><code>public partial class MainWindow : Window
  {
          dbSet dbContext = new dbSet();
  
          public MainWindow()
          {
              InitializeComponent();
          }
  
          private void Window_Loaded(object sender, RoutedEventArgs e)
          {
             var names = dbContext.People.SqlQuery("Select FirstName FROM person").ToArray(); 
              dgMain.ItemsSource = names;
              dgMain.SelectedIndex = 0;
          }
  </code></pre>
  
  <p>But this always gives an error </p>
  
  <blockquote>
    <p>The data reader is incompatible with the specified 'dbSet.Counselor1'. A member of the type, 'CounselorID', does not have a corresponding column in the data reader with the same name.</p>
  </blockquote>