title: FileHelpers library - Is it possible to change field's date format at runtime?
body: <p>Using FileHelpers library version 3.0.1 .</p>
  
  <p>Say you define a field to import from a csv file like this :</p>
  
  <pre><code>    [FieldTrim(TrimMode.Both)] 
      [FieldQuoted('"', QuoteMode.OptionalForBoth, MultilineMode.NotAllow)]
      [FieldConverter(ConverterKind.Date, "d-MMMM-yyyy")]
      public DateTime DOB;
  </code></pre>
  
  <p>Now, the csv field is expected to be in the date format "d-MMMM-yyyy", and set at compile time. I have a requirement at runtime to (sometimes) change this format to "d-MMMM-yy". </p>
  
  <p>The format to use depends on the source file - some files have 2 digit years, others have 4 digit years. I will know at program startup which format to use. </p>
  
  <p>Is this possible with FileHelpers ? I suppose I could add a string column like : </p>
  
  <pre><code>[FieldTrim(TrimMode.Both)] 
  [FieldQuoted('"', QuoteMode.OptionalForBoth, MultilineMode.NotAllow)]
  public string DOBAsString; 
  </code></pre>
  
  <p>, and get FileHelpers to read the data into this field, and convert it to the DOB field myself in a loop. Is there a cleaner way ? </p>