ASP.net Converting inputbox string to integer?

Question

I have been trying for ages to convert a string taken from an input box in my asp form and converting it to an integer.

This integer variable will then be used for a database operation I have planned.

Here is what I have tryed:

 string mytxtCHI = txtID.Text;
            int @CHI = Convert.ToInt16(mytxtCHI);

Error:

System.FormatException {"Input string was not in a correct format."}

Things I have tried:

-  string mytxtCHI = txtID.Text;
            int myNewID=(Int32.Parse(txtID.Text));

Thankyou for your time :)

looks like you don't have a number in your input box. What is the text? — BrokenGlass
– BrokenGlass, Commented Jul 15, 2011 at 20:54
What value are you putting in your textbox? A simple Parse() should work, although the answers below suggesting TryParse() are a lot more robust. — Jason
– Jason, Commented Jul 15, 2011 at 20:57
The moral of all the answer(s), always TryParse since you never know what the users going to give you in a textbox... — Zachary
– Zachary, Commented Jul 15, 2011 at 20:57
you are right, I ran RUN-TO-CURSOR and for some reason the textbox control is not picking the entry I make. However, when I hard code the value to a variable, the textbox picks it. See below: string test2 = "running nuts"; txtID.Text = test2; — TerryTheTerminator
– TerryTheTerminator, Commented Jul 15, 2011 at 20:58

Senad Meškin · Accepted Answer · 2011-07-15 21:21:33Z

1

Your way is correct, but what you should do to avoid errors

int myNewID = 0;

    if(int.TryParse(txtID.Text, out myNewID))
     {
        //your code here
    }
    else
    {
       //your error handling here
    }

edited Jul 15, 2011 at 21:21

answered Jul 15, 2011 at 20:56

Senad Meškin

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1 Comment

TerryTheTerminator Over a year ago

Thanks developers, TryParse Worked

Peter · Accepted Answer · 2011-07-15 20:55:37Z

1

You should use tryparse:

  string mytxtCHI = txtID.Text;
  int number;
  bool result = Int32.TryParse(mytxtCHI , out number);
  if (result)
  {
     Console.WriteLine("Converted '{0}' to {1}.", mytxtCHI , number);         
  }
  else
  {
     if (value == null) value = ""; 
     Console.WriteLine("Attempted conversion of '{0}' failed.", mytxtCHI );
  }

answered Jul 15, 2011 at 20:55

Peter

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Comments

James McCormack · Accepted Answer · 2011-07-15 20:57:30Z

1

Put a breakpoint on the line in Visual Studio. In debug mode, run to the breakpoint, and hover over txtID.Text to see what's in it.

When in the page lifecycle are you checking this value? Check it after Page Init. Check HttpRequest.Form to see what came down the wire.

answered Jul 15, 2011 at 20:57

James McCormack

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Comments

Jim Mischel · Accepted Answer · 2011-07-15 20:56:06Z

0

You should use Int.TryParse, and handle the case when the value isn't a valid integer.

string mytxtCHI = txtId.Text;
int val;
if (!int.TryParse(mytxtCHI, out val))
{
    // error here, value was not a valid integer.
}
// here, val contains the value, expressed as an integer.

answered Jul 15, 2011 at 20:56

Jim Mischel

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Comments

hungryMind · Accepted Answer · 2011-07-15 20:57:13Z

0

Use watch window or System.Diagnostics.Debug.WriteLine(mytxtCHI) to check what's the value you are passing, is it blank?

answered Jul 15, 2011 at 20:57

hungryMind

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