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. codeproject.com/Articles/93804/… — Spacemancraig
– Spacemancraig, Commented Jul 25, 2012 at 18:31

naspinski · Accepted Answer · 2012-07-25 18:32:34Z

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, 2012 at 18:32

naspinski

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1 Comment

Oscar Arango Over a year ago

thanks for the help. had to change int to double but it worked after.

Stu · Accepted Answer · 2012-07-25 18:32:00Z

1

Why don't you use a MaskedTextBox?

answered Jul 25, 2012 at 18:32

Stu

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Comments

David B · Accepted Answer · 2012-07-25 18:29:03Z

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

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

hspain · Accepted Answer · 2012-07-25 18:30:29Z

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;

Daniel Mošmondor · Accepted Answer · 2012-07-25 18:48:47Z

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 · Accepted Answer · 2012-07-25 21:55:23Z

-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, 2012 at 21:55

answered Jul 25, 2012 at 20:19

LOZ

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3 Comments

Jeff Mercado Over a year ago

What does that have to do with the question?

LOZ Over a year ago

for some reason the rest of the post doesnt show, i included a code.

Jeff Mercado Over a year ago

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.

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