private void button1_Click(object sender, EventArgs e) { if (textBox1.TextLength == 0 || comboBox1.SelectionLength == 0 || textBox2.TextLength == 0) { MessageBox.Show("Enter value"); return; } DB.addDataToApplicationsEmployee(textBox1.Text, comboBox1.Text, textBox2.Text, dateTimePicker1.Value); loadInfoToTable(); }