title: how to get nth letter of english alphabet
body: <p>Is there any way to get nth letter of English alphabet? I want smt similar to this:</p>
  
  <pre><code>string letter = EnglishAlphabet.GetLetter(5);
  //result -&gt; letter is 'E'
  </code></pre>
  
  <p>I want to use this according to count of my list. If there is 3 elements on my list so "D:D" is enough for me but there is 4 elements then "E:E". I want use this string here:</p>
  
  <pre><code> Excel.Range chartRange;    
   Excel.ChartObjects xlCharts = (Excel.ChartObjects)xlWorkSheet.ChartObjects(Type.Missing);
   Excel.ChartObject myChart = xlCharts.Add(5, 5, 540, 160);
   Excel.Chart chartPage = myChart.Chart;    
   chartRange = xlWorkSheet.get_Range("A:A", "D:D");//"D:D" changes according to size of the list??
  </code></pre>
  
  <p>Any suggestions? Thanks</p>