private void ViewButton_Click(object sender, EventArgs e) { ClearDataGridView(); if (FilterByComboBox.SelectedItem.ToString() == "None") { UpdateDataGridView(Data.GetAll()); } else if (CheckID(FilterIDBox)) { ValueError.Clear(); int id = Convert.ToInt32(FilterIDBox.Text); DataTable dataTable = GetDataTable(id); UpdateDataGridView(dataTable); } }