Allow only integers in TextBoxes

Question

I'm having a problem with checking textboxes and making sure there's only integers in them.

So far I'm able to confirm that there's text in the textboxes, but checking if they're integers isn't working. Here's my code that so far works.

if (textBox1.Text.Length == 0)
{
    errorProvider1.SetError(textBox1, "need Cost of Disks");
    return;
}
if (textBox2.Text.Length == 0)
{
    errorProvider2.SetError(textBox2, "need Total disks in package");
    return;
}
if (textBox3.Text.Length == 0)
{
    errorProvider3.SetError(textBox3, "need the Gigabyte per disk");
    return;
}
try
{
    Double[] myValues = new Double[3];
    myValues[0] = Double.Parse(textBox1.Text);
    myValues[1] = Double.Parse(textBox2.Text);
    myValues[2] = Double.Parse(textBox3.Text);

    Double ppd = myValues[0] / myValues[1] / myValues[2];

    ppd = Math.Round(ppd, 3, MidpointRounding.AwayFromZero);

    label4.Text = ppd.ToString();
}
catch (FormatException)
{
    //errorProvider1.SetError(label4, "testing1");

    //errorProvider2.SetError(label4, "testing2");

    //errorProvider3.SetError(label4, "testing3");
    return;
}

I would recommend using regular expressions. http://www.codeproject.com/Articles/93804/Using-Regular-Expressions-in-C-NET — Spacemancraig, Jul 25 '12 at 18:31

score 2 · Accepted Answer · answered Jul 25 '12 at 18:32

2

Using your current pattern, something like this:

int tester;
if (!Int32.TryParse(textBox1.Text, out tester))
{
    errorProvider1.SetError(textBox1, "must be integer");
    return;
}

answered Jul 25 '12 at 18:32

naspinski

34,020
36
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167

thanks for the help. had to change int to double but it worked after. – Oscar Arango Jul 25 '12 at 19:03

score 1 · Answer 2 · answered Jul 25 '12 at 18:32

1

Why don't you use a MaskedTextBox?

answered Jul 25 '12 at 18:32

Stu

15,675
4
43
74

score 0 · Answer 3 · answered Jul 25 '12 at 18:29

0

Override the Validating event in your form's textboxes and then you can do a TryParse on the contents.

public void textBox1_Validating(...)
{
  // TryParse
}

answered Jul 25 '12 at 18:29

David B

2,688
18
25

score 0 · Answer 4 · answered Jul 25 '12 at 18:30

0

You can use the int.TryParse method to check if the string is an integer:

int n = 0;
bool isNumber = int.TryParse(textBox1.Text, out n);

if (!isNumber)
   return;

answered Jul 25 '12 at 18:30

hspain

17,528
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score 0 · Answer 5 · answered Jul 25 '12 at 18:48

If you don't want to permit ANYTHING except numbers into the editbox, hook into keyboard events, check for characters that aren't digits and cancel them out.

When you sort out what events are needed on one textbox, just reuse same event on others, since you don't have to copy events around.

LOZ · Answer 6 · 2012-07-25T21:55:23.247

-1

If you ever start using ajax tool kit, keep this for your records

<ajaxToolkit:FilteredTextBoxExtender ID="FilteredTextBoxExtender1" TargetControlID="FUND_CD" FilterType="Custom" ValidChars="1234567890" runat="server">
                        </ajaxToolkit:FilteredTextBoxExtender>

edited Jul 25 '12 at 21:55

answered Jul 25 '12 at 20:19

LOZ

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What does that have to do with the question? – Jeff Mercado Jul 25 '12 at 20:46
for some reason the rest of the post doesnt show, i included a code. – LOZ Jul 25 '12 at 21:54
Ah ok, I didn't realize there was more in your post. But then again, if you looked closely at the question, it's about WinForms, not ASP.net so this wouldn't be very helpful to the question. – Jeff Mercado Jul 25 '12 at 22:00

Allow only integers in TextBoxes

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