RegularExpressionValidator in asp.net not working for 1 or 2 digit number

Question

I've read other answers to other questions about RegularExpressionValidator but they haven't helped. I'm working on an ASP.NET C# app and I have a text field that needs to be a 1 or 2 digit number. Here's the control:

<asp:TextBox 
    ID="Hunt_Daily_Sitting_hrs" 
    runat="server" 
    class="form-control" 
    placeholder="hours" 
    type="number"></asp:TextBox>

As written, even though it specifies type="number", it allows mathematical operators. So people have been entering "6-8" as in "6 to 8 hours". On this page, the regular expression ^\d{1,2}$ flags such an entry. However, in my app, the line

<asp:RegularExpressionValidator 
    ID="HuntSitRegexp" 
    Display="Dynamic" 
    ControlToValidate="Hunt_Daily_Sitting_hrs" 
    ValidationExpression="^\d{1,2}$" 
    runat="server" 
    ErrorMessage="Please enter a number from 1-24" 
    Font-Size="Large" 
    ForeColor="Red" />

does not. A 3-digit number is immediately flagged, but an entry such as "6-8" is NOT immediately flagged. However, an entry such as "6-8" DOES fail submission in that the "Submit" button does nothing, indicating that Javascript validation has failed. So the user is left thinking, "What's wrong with the form? It won't submit but there is no error message."

Why not use a dropdown with the numbers 1-24 instead of a text box? — juharr, Aug 25 '17 at 18:52
Sounds like you need to fix your web page so that it displays validator error messages. — Robert Harvey, Aug 25 '17 at 18:57
It does show validator error messages. For example, it shows an error message for a three digit number. It just doesn't show it for one or two digits and a math operator. — James Alesi, Aug 25 '17 at 20:08
If you want the regex to work, I think you need to change `type="number"` to `type="text"` — Wiktor Stribiżew, Aug 25 '17 at 20:18
I actually ended up using this answer because I decided that I wanted to allow floats as well. https://stackoverflow.com/a/24638656/7410516 — James Alesi, Aug 27 '17 at 13:58

Wiktor Stribiżew · Accepted Answer · 2017-08-25T22:58:07.607

1

The ValidationExpression="^\d{1,2}$" is fine, but the regex checking is not enabled for an input of number type.

So, you need to change the asp:TextBox control type="number" to type="text".

edited Aug 25 '17 at 22:58

answered Aug 25 '17 at 22:51

Wiktor Stribiżew

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Rex · Answer 2 · 2017-08-25T19:02:39.890

0

Try this Reg Ex instead

^[0-9]{1,2}$

edited Aug 25 '17 at 19:02

answered Aug 25 '17 at 18:57

Rex

521
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score 0 · Answer 3 · answered Aug 29 '17 at 15:45

I think the answer with changing the type is correct one. However, I noticed that your ValidationExpression="^\d{1,2}$"
and ErrorMessage="Please enter a number from 1-24" do not match. It will take any 1-2 digit number.

The RegEx expression which will match only numbers 1-24 is following: ^(\d)$|^(1\d)$|^(2[0-4])$

RegularExpressionValidator in asp.net not working for 1 or 2 digit number

3 Answers3