title: When creating a csv file, Excel shows double quotes
body: <p>I've created a .csv file using C# and when I open this file in Excel, it shows the double quotes in the cells.</p>
  
  <p>When I open the csv in Notepad++ I see that are quotes are there and everything looks right to me. Here's a part of my csv:</p>
  
  <pre><code>"CertificaatNummer", "Data", "Inleg", "Getekend", "Ingangsdatum", "Betaalmethode", "Status", "Bonus", "Aankoopkoers", "Korting", "Garantiewaarde", "Betaalde termijnen", "Inleg nominaal", "Tweede naam", "Recht op bonus maand", "Begunstigde", "Product", "Incasserekening", "Uitbetaalrekening"
  "126136", "some data with, a comma", "118.34", "True", "28-1-1999 00:00:00", "Cash", "C02", "0.00", "531,940", "0,000", "0.00", "0", "0.00", "", "False", "P.H. Bloemink", "Cash-Click", "", "260952095"
  "137190", "other data", "0.00", "True", "23-12-1999 00:00:00", "Cash", "C02", "0.00", "660,620", "0,000", "0,00"
  </code></pre>
  
  <p>When I open this file in Excel it treats the comma in <code>some data with, a comma</code> as a new column. So I get <code>"Some data with</code> in one cell and <code>a comma"</code> in antother cell. As you see, Excel doesn't care about the double quotes. </p>
  
  <p>Here's what my code looks like (simplified):</p>
  
  <pre><code>var content = new List&lt;string&gt;();
  
  // Add headers
  content.Add("\"Header 1\", \"Header 2\", \"Header 3\", \"Header 4\"");
  
  // Add content
  content.Add("\"123456\", \"some data with, a comma\", \"118.34\", \"True\"");
  // etc..
  
  // I let a function create my file content
  using (var stream = new MemoryStream())
  using (var writer = new StreamWriter(stream))
  {
      foreach (var line in this.content)
      {
          writer.WriteLine(line);
      }
  
      writer.Flush();
      return stream.ToArray();
  }
  
  // finally I return the file content to the browser with 
  // HttpContext.Response.AddHeader("content-disposition", "file;name=" + fileName);
  </code></pre>
  
  <p>The question is, which part of my code do I have to edit so Excel will display my file properly? I rather want to edit my code then executing some tricks in Excel.</p>