this is my code
int sum = int.Parse(TextBox5.Text) + int.Parse(TextBox6.Text) + int.Parse(TextBox7.Text);
Label1.Text = String.Format("{0}", sum);
when I enter all three textboxes it runs clearly but if i keep any one or two of them null it gives error...
input was not in correct formate ..
how can I solve this error.....