private void SearchButton_Click(object sender, EventArgs e) { if (IDTextbox.Text != "") { searchCrit = new Topics { Title = TopicTextbox.Text, ID = Convert.ToInt32(IDTextbox.Text) }; } else { searchCrit = new Topics { Title = TopicTextbox.Text }; } dataGridView1.DataSource = DependencyFacade.GetTopics(searchCrit); dataGridView1.Columns[3].HeaderText = "Teacher name"; dataGridView1.Columns[4].HeaderText = "Teacher surname"; for (int i = 0; i < 5; i++) { DataGridViewColumn col = dataGridView1.Columns[i]; col.Width = i == 1 ? 250 : 70; } }