private void bAgregar_Click(object sender, EventArgs e)
        {
            Registrar_Agenda.EditAgenda editForm = new Registrar_Agenda.EditAgenda();
            editForm.ShowDialog();

            if (editForm.DialogResult == DialogResult.OK) {
                FillDgv();
            }
        }
        private void dgvAgenda_CellContentClick(object sender, DataGridViewCellEventArgs e)
        {
            if (dgvAgenda.Columns[e.ColumnIndex].HeaderText == "Seleccionar") {
                Registrar_Agenda.EditAgenda formEdit = new Registrar_Agenda.EditAgenda(agendas[dgvAgenda.Rows[e.RowIndex].Cells["id"].Value.ToString()]);
                formEdit.ShowDialog();

                if (formEdit.DialogResult == DialogResult.OK) {
                    FillDgv();
                }
            }
        }