C# Input string was not in a correct format

Question

Working on parsing from a text box to int to get into the incrementHour method as shown.

if (txtHourPlus.Text != String.Empty)
            {
                time1.incrementHour(int.Parse(txtHour.Text));

            }

And in the time class: (the time1 objects class)

 public int incrementHour(int step)
        {
            if (step > 0 && hour < 24)
            {
                //step = step % hour;
                hour = (hour + step) % 24;
                time.AddHours(hour);
                return hour;
            }//end of if

            else
            {
                MessageBox.Show("Please enter a positive number.");

                return 0;
            }//end of else
        }//end of incrementHour

not sure why i'm getting this error. I'm converting it to the corrent data type. Because it accepts an int variable.

Alright well i got it to take the value (small mistake >.> Don't even wanna say it) However as someone already said the method probably needs work because i'm trying to change the Datetime value that i get in the first place and add an hour or subtract and etc etc.

Can you post the stack trace? I'm assuming the error is coming from the int.parse. — AJ.
– AJ., Commented Jan 28, 2011 at 22:11
you should prefer to use String.IsNullOrWhite space instead of comparing to String.Empty :) — Muad'Dib
– Muad'Dib, Commented Jan 28, 2011 at 22:13
@Muad'Dib: Have you ever seen TextBox.Text return null? I would be very surprised if that ever happened... and if it did, I think I'd rather find out about it... — Jon Skeet
– Jon Skeet, Commented Jan 28, 2011 at 22:13
Maybe the input string is not in a correct format. Like the error message. — Jonathan Wood
– Jonathan Wood, Commented Jan 28, 2011 at 22:15

Jon Skeet · Accepted Answer · 2011-01-28 22:10:32Z

3

That will happen if someone has typed "foo" into the text box, for example. You should use int.TryParse instead, which lets you detect the error without an exception being thrown.

I notice that you're not actually using the return value of your method though - just like you're not using the return value of time.AddHours. You are aware that DateTime.AddHours doesn't actually modify the value you're calling it on, aren't you? (I suspect you'll need to tweak that method quite a bit, actually... there are various potential problems with it, depending on exact what you're trying to do.)

(Finally, I'd change the method name to IncrementHour to comply with .NET conventions.)

answered Jan 28, 2011 at 22:10

Jon Skeet

1.5m893 gold badges9.3k silver badges9.3k bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

jocull Over a year ago

int test = 0; bool result = int.TryParse("some string", out test);

David Brewer Over a year ago

>.> wasn't totally aware of that. All i'm trying to do is be able to increment the hours and minutes with this program. I'm just having an issue just doing that.

horatio · Accepted Answer · 2011-01-28 22:22:06Z

2

you are testing txtHourPlus for emptiness, but then parsing and passing txtHour. typo (?)

answered Jan 28, 2011 at 22:22

horatio

1,4368 silver badges7 bronze badges

2 Comments

David Brewer Over a year ago

/face palm yeah that was my issue. Now i'm just working on getting the value that i pass to actually change the time.

Scott Chamberlain Over a year ago

+1 for the only person who caught the real error not just the bad practices.

Yes - that Jake. · Accepted Answer · 2011-01-28 22:11:34Z

1

If your input isn't parsable as an integer, attempting to parse it will raise an exception. Validate or use Int32.TryParse()

answered Jan 28, 2011 at 22:11

Yes - that Jake.

17.2k15 gold badges73 silver badges99 bronze badges

Comments

code4life · Accepted Answer · 2011-01-28 22:24:26Z

0

Change this part of your code:

if (txtHour.Text != String.Empty)
{
    int parsedValue;

    if (int.TryParse(txtHour.Text, out parsedValue))
    {
        time1.incrementHour(parsedValue);
    }
    else
    {
        // non-numeric value was entered into the textbox - handle accordingly.
    }
}

answered Jan 28, 2011 at 22:24

code4life

15.8k8 gold badges56 silver badges82 bronze badges

Collectives™ on Stack Overflow

C# Input string was not in a correct format

4 Answers 4

2 Comments

2 Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

2 Comments

2 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related