Currency conversion code issue

Hi all, i am looking to convert dollar to local currency of my country (Cfa), i use combobox, the result i get example on the catch is wrong

here is my code:

private void button2_Click(object sender, EventArgs e)
{
int selectIndex = dev1.SelectedIndex;
int money = int.Parse(mnt1.Text);
int rate = int.Parse(mnt2.Text);
if (dev1.SelectedItem.ToString()=="Dollar" && dev2.SelectedItem.ToString()=="Cfa")
{
int conversion = money * rate;
int convStr = Convert.ToInt32(conversion);
total.Text = convStr.ToString();
}

thank you for helping me see a little clearer