title: C#: 'IEnumerable<Student>' does not contain a definition for 'Intersect'
body: <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>