commission rate display wrong when write commission textbox1

my problem is cannot able to write any number in commission textbox (textbox1) and display result in textbox2 that represent commision rate .

commision rate = (commission/amount ) * 100

I have 3 text boxes

textbox1 : represent Commission

Commission=(amount * rate)/100

textbox2 : represent CommissionRate

CommissionRate=(Commission/amount)*100

txtLgAmount represent amount

private void textBox1_TextChanged(object sender, EventArgs e)
{
if (!string.IsNullOrEmpty(textBox1.Text) && !string.IsNullOrEmpty(txtLgAmount.Text))
{
textBox2.Text = ((Convert.ToDecimal(textBox1.Text) / Convert.ToDecimal(txtLgAmount.Text))*100).ToString();
}
else
{
textBox2.Text = "";
}
}

image problem attached below