title: Add Column to DataGridView with dynamic calculations
body: <p>Is there any possibility to add a column to a <code>DataGridView</code> to dynamic calculate values?</p>
  
  <p>I have a <code>DataGridView</code> populated by a <code>LINQ</code> query (ToList). I'm using <code>EF6</code> (Database first).</p>
  
  <p>I need to add one column not binded to query collection that calculates the days between 2 dates.</p>
  
  <p>Here's my <code>DataGridView</code> populate list:</p>
  
  <pre><code>public class Recl
      {
          public int ID { get; set; }
          public string Concelho { get; set; }
          public string Entidade { get; set; }
          public string LC { get; set; }
          public string Classificacao { get; set; }
          public string TipoR { get; set; }
          public string TipoE { get; set; }
          public string Identificador { get; set; }
          public string Estado { get; set; }
          public decimal? Custos { get; set; }
          public string Descricao { get; set; }
          public DateTime DataR { get; set; }
          public DateTime DataE { get; set; }
          public DateTime? DataRespostaEE { get; set; }
          public DateTime? DataRespostaC { get; set; }
      }
  
      public IEnumerable&lt;Recl&gt; LoadData()
      {
          var ctx = new IWMJEntities();
          var fillrecl = (from p in ctx.tblRecl.AsQueryable()
                           join c in ctx.tblConc on p.ConcID equals c.ConcID
                           join e in ctx.tblEnt on p.EntID equals e.EntID
                           join ex in ctx.tblLC on p.LCID equals ex.LCID
                           join cl in ctx.tblClassificacao on p.ClassificacaoID equals cl.ClassificacaoID
                          join tp in ctx.tblTipoR on p.TipoRID equals tp.TipoRID
                          join te in ctx.tblTipoE on p.TipoEID equals te.TipoEID
                          select new Recl
                          {
                               ID = p.ReclID,
                               Concelho = c.NomeConcelho,
                               Entidade = e.Nome,
                               LC = ex.Codigo,
                               Classificacao = cl.Classificacao,
                               TipoR = tp.TipoR,
                               TipoE = te.TipoE,
                               Identificador = p.Identificador,
                               Estado = p.Estado,
                               Custos = p.Custos,
                               DataR = p.DataR,
                               DataE = p.DataE,
                               DataRespostaEE = p.DataRespostaEmpresa,
                               DataRespostaCliente = p.DataRespostaCliente
                           }).ToList();
          return fillrecl;
      }
  </code></pre>
  
  <p>And the call to load <code>DataGridView</code> from Load Event:</p>
  
  <pre><code>datagrid.DataSource = LoadData();
  </code></pre>
  
  <p>How can I add one more column (Days) which calculate diference in Days between <code>DateTime.Now</code> and <code>DataE</code>?</p>
  
  <p>Where do I put this new column on code?</p>