title: LINQtoCSV cannot assign IEnumerable to List - ArgumentNullException was unhandled
body: <p>I have csv file that I read and store in IEnumerable data_values. The only problem is that when I want to read it with MessageBox.Show() then it throws ArgumentNullException was unhandled. I tried to do it like if(data_values != null) but it doesn't work. I tried many many solutions but none works.
  All I want to do is to assign data from date_values to for example temperatures_values and show it.
  This is what it looks like:</p>
  
  <pre><code>class CSVdata
  {
      public List&lt;data&gt; data_var = new List&lt;data&gt;();
      public IEnumerable&lt;data&gt; data_values;
      public CSVdata()
      {
           CsvFileDescription file_description = new CsvFileDescription { 
              SeparatorChar = ';',
              FirstLineHasColumnNames = true,
              EnforceCsvColumnAttribute = true
              };
  
          CsvContext cc = new CsvContext();
          data_values = cc.Read&lt;data&gt;("C:/Users/GreenScreen/Desktop/Transbud_pomiary_csvFile.csv", file_description);
          data_var = data_values.ToList();
      }
  }
  </code></pre>
  
  <p>And I want to show it with:</p>
  
  <pre><code>    private void button_ReadData_Click(object sender, EventArgs e)
      {
          CSVdata csvData = new CSVdata();
          MessageBox.Show(csvData.data_var[5].ToString());
      }
  </code></pre>