01.private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
02.{
03. if (this.comboBox1.SelectedIndex < 0) return;
04.
05. double result;
06.
07. if (double.TryParse(this.textBox1.Text, out result))
08. {
09. double percent = 0.0;
10.
11. switch (this.comboBox1.SelectedIndex)
12. {
13. case 0 :
14. percent = 0.2;
15. break;
16. case 1 :
17. percent = 0.3;
18. break;
19. case 2 :
20. percent = 0.5;
21. break;
22. }
23.
24. this.BeginInvoke((MethodInvoker)delegate {
25. this.comboBox1.Text = string.Format("{0} = {1}", this.comboBox1.Text, (result * percent).ToString("N2"));
26. });
27. }
28.}
