MVC PivotTable

I need to return the result of the procedure, I put a fixed value just to perform my tests but it will have a typed input, in datepick. But I can not create the list for the columns.

Here is the snippet of code:

public string dtaTotal(string dtaini, string dtafinal)
    {

       List<string> dtatot = new List<string>();

       var result = "'" + dtaini + "'" + "," + "'" + dtafinal + "'";

       return result;
    }

    private List<Campanha> BuscaCampanhas()
    {
       using (SqlCommand command = new SqlCommand("exec pr_DashBrokerCampanhas '01-09-2018', '10-09-2018'", DBConnection))
       {
           DBConnection.Open();
           using (SqlDataReader reader = command.ExecuteReader())
           {
               List<Campanha> _listCampanhas = new List<Campanha>();

                  while (reader.Read())
                  {
                      _listCampanhas.Add(

                          new Campanha
                          {
                              DescCampanha = reader["DescCampanha"].ToString(),
                              Total = reader["Total"].ToString(),
                              Columns = dtaTotal()
                          }
                      );
                  }

               DBConnection.Close();
               return _listCampanhas;

           }
       }
    }

Campaign Class:

public class Campanha
{
    public string DescCampanha { get; set; }
    public string Total { get; set; }
    public List<string> Columns { get; set; }
}

public class Dashboard
{
    public List<Envio> Envios { get; set; }
    public List<Broker> Brokers { get; set; }
    public List<Campanha> Campanhas { get; set; }
}

Index controller:

        var DashboardContent = new Dashboard();

        DashboardContent.Envios = BuscaTodosEnvios();
        DashboardContent.Brokers = BuscaBrokers();
        DashboardContent.Campanhas = BuscaCampanhas();

        return View(DashboardContent);