private DataTable Consultar()
        {
            var filtro = new StringBuilder();

            if (StringHelpers.IsDate(this.txtDe.Text))
            {
                filtro.Append(" AND A.DataEmissao >= CONVERT(DATETIME, '" + this.txtDe.Text + "', 103) ");
            }

            if (StringHelpers.IsDate(this.txtAte.Text))
            {
                filtro.Append(" AND A.DataEmissao <= CONVERT(DATETIME, '" + this.txtAte.Text + "', 103) ");
            }

            if (this.cbEmpresa.SelectedValue.ToInt() > 0)
            {
                filtro.Append(" AND A.Empresa = '" + this.cbEmpresa.SelectedValue + "' ");
            }

            if (!string.IsNullOrEmpty(this.txtFilial.Text))
            {
                filtro.Append(" AND A.Filial = '" + this.txtFilial.Text + "' ");
            }

            if (!string.IsNullOrEmpty(this.txtMemorando.Text))
            {
                filtro.Append(" AND A.Memorando = '" + this.txtMemorando.Text + "' ");
            }

            if (!string.IsNullOrEmpty(this.txtDUE.Text))
            {
                filtro.Append(" AND C.DUE = '" + this.txtDUE.Text + "' ");
            }

            if (!string.IsNullOrEmpty(this.txtChaveDUE.Text))
            {
                filtro.Append(" AND C.ChaveAcesso = '" + this.txtChaveDUE.Text + "' ");
            }

            if (!string.IsNullOrEmpty(this.txtChaveNF.Text))
            {
                filtro.Append(" AND A.ChaveNF LIKE '%" + this.txtChaveNF.Text + "%' ");
            }

            if (!string.IsNullOrEmpty(this.txtNumeroNF.Text))
            {
                filtro.Append(" AND A.NumeroNF = '" + this.txtNumeroNF.Text + "' ");
            }

            if (!string.IsNullOrEmpty(this.txtCNPJ.Text))
            {
                filtro.Append(" AND A.CNPJNF = '" + this.txtCNPJ.Text.Replace(".", "").Replace("/", "").Replace("-", "") + "' ");
            }

            return(_notaFiscalDAO.ListagemMemorando(filtro.ToString()));
        }