C#: 'IEnumerable<Student>' does not contain a definition for 'Intersect'
<p>It's been long since I write a single line of code so, please, be patient if I am asking a dumb question.</p>

<p>Even though the IntelliSense shows the Intersect method after Names, I get the following error when trying to compare two IEnumerables.  </p>

<p>I am trying to compare the result of a database query versus an ordered list in the html.</p>

<blockquote>
  <p>'IEnumerable' does not contain a definition for 'Intersect' and the best extension method overload
  'Queryable.Intersect(IQueryable,
  IEnumerable)' requires a receiver of type
  'IQueryable'</p>
</blockquote>

<pre><code>namespace Data.Repositories
{
    public class StudentsRepository
    {
        public class Student
        { 
            public string FullName { get; set; }
        }

        public static IEnumerable&lt;Student&gt; GetData(string CardNumber, string Section)
        {
            // FullName varchar(300) in Database
            return CommonFunctions.ExecuteReader1&lt;Student&gt;(QryStudentSectionDetails(CardNumber, Section)).AsQueryable();
        }
    }
}


namespace Tests.ActionsLibrary.StudentPaper
{
    public class StudentActions:TestBase
    {
        bool IsMatch = false;

        // Get Names from DataBase
        IEnumerable&lt;Student&gt; Names = GetData(CardNumber, Section);

        // Get Names from Ordered list in HTML
        IEnumerable&lt;IWebElement&gt; OrderedList = driver.FindElements(By.XPath("//li[@ng-repeat='Names']"));

        if (Names.Count() == OrderedList.Count() &amp;&amp; Names.Intersect(OrderedList).Count() == OrderedList.Count()) // The error is shown here.
        { IsMatch = true; }
</code></pre>

<p>I wonder what I am doing wrong.  Any help will be greatly appreciated.  Thanks.</p>

<p>At the end the code looks like this:</p>

<pre><code>    IEnumerable&lt;string&gt; Names = GetData(CardNumber, Section).Select(s =&gt; s.FullName);
    IEnumerable&lt;string&gt; OrderedList = driver.FindElements(By.XPath("//li[@ng-repeat='Names']")).Select(i =&gt; i.Text);
</code></pre>

<p>Thank you, very much for your help.</p>