Question

I have the following code to do a some very simple validation for a textbox

    if(txtInStock.Text.Length == 0)
        txtInStock.Text = Convert.ToString(0);

    if (txtInStock.Text.Length == 0)
        txtOnOrder.Text = Convert.ToString(0);

    int inStockAmt = Convert.ToInt32(txtInStock.Text);
    int onOrderAmt = Convert.ToInt32(txtOnOrder.Text);

This works fine when Text != 0 , but when Text == 0 I get a FormatException saying the string is not of the proper format. How can I correct this?

Answer 1

Your problem is here:

if (txtInStock.Text.Length == 0)
    txtOnOrder.Text = Convert.ToString(0);

You’re checking the length of one text box and setting the text of another. Change it to this:

if (txtOnOrder.Text.Length == 0)
    txtOnOrder.Text = Convert.ToString(0);

Also, is there a reason you’re using Convert.ToString(0) instead of just "0"? I don’t particularly recommend using this approach for data validation, but this should correct the problem.