Error when pressing button in Add User Information listing application

Question

Error (input string was not in a correct format) when button is pressed in Add User Information listing application

int Guestid =  Convert.ToInt32((sender as LinkButton).CommandArgument); 
if (sqlcon.State == ConnectionState.Closed)
    sqlcon.Open();

SqlDataAdapter sqlDa = new SqlDataAdapter("GuestViewByID]", sqlcon);

It's not working as you can see in the picture.

Answer 1

Well, you don't check, show to us what the value of CommandArgument was.

Worse yet, you posted a screen shot in which you could have placed your cursor over the value in the debugger.

So, you need to deal with the fact that CommandArugment might pass a empty string (""), and thus your int conversion will fail.

As a result, try this, and if CommandArugment = "", then you get 0.

int Guestid;
int.TryParse((sender as LinkButton).CommandArgument, out Guestid);

However, while this will fix the error, it DOES NOT fix your logic, since your logic assumes that you supposed to get a value number (int), and you are not.

So, you REALLY need to determine why your commandArgument is not being set to a number, or why it is failing.

So, the above code will fix the error, but not your program logic.