Textbox regex validation is not working in uwp

Question

This is an example of custom regex validation for numbers only that is provided in official doc of Windows Community Toolkit of UWP here TextBox Regex extensions in toolkit.

<StackPanel Margin="10,0,10,0">
    <TextBox Name="PhoneNumberValidator"
             extensions:TextBoxRegex.Regex="^\s*\+?\s*([0-9][\s-]*){9,}$"
             Header="Text box with Regex extension for phone number, validation occurs on TextChanged"
             HeaderTemplate="{StaticResource HeaderTemplate}"
             Style="{StaticResource TextBoxRegexStyle}" />
    <StackPanel Orientation="Horizontal">
        <TextBlock Text="Is Valid: " />
        <TextBlock Text="{Binding (extensions:TextBoxRegex.IsValid), ElementName=PhoneNumberValidator, Converter={StaticResource StringFormatConverter}}" />
    </StackPanel>

</StackPanel>

It works but if i change the regex and use a custom regex /^(?!\s*$).+/ for NotNullOrEmpty validation then it doesn't work. mean ext:TextBoxRegex.IsValid always returns false. Why ?

Do you use it as in the docs? `extensions:TextBoxRegex.Regex="^(?!\s*$).+"`? — Wiktor Stribiżew, Jul 10 '20 at 07:49
`xmlns:ext="using:Microsoft.Toolkit.Uwp.UI.Extensions"` yeah same way except i'm using `ext` — Hammas, Jul 10 '20 at 07:53
and idk who down voted the question without even saying a single word :( — Hammas, Jul 10 '20 at 07:54
What are you trying to match with your `^(?!\s*$).+` RegEx? It is kinda odd to me. — Cleptus, Jul 10 '20 at 07:57
@bradbury9 sir. from this answer https://stackoverflow.com/questions/7967075/regex-for-not-empty-and-not-whitespace i got this regex to see if text box text is empty or null — Hammas, Jul 10 '20 at 08:01
@bradbury9 idk if you got me or not but that's how it should work in case of Comunity toolkit for Uwp for text box text validation. — Hammas, Jul 10 '20 at 08:01
So you didn't use it as in the docs. You must have included the regex delimiters into the regex pattern. The validation is working. — Wiktor Stribiżew, Jul 10 '20 at 19:22

score 0 · Accepted Answer · edited Jul 17 '23 at 15:36

I tested the regular expression you provided in the WindowsCommunityToolkit Sample App:

<TextBox extensions:TextBoxRegex.Regex="(?!^$)([^\s])"
         .../>

It works fine, that is, after entering text, it shows the result as True.

Please note that the regular expression itself does not contain the first and last /, it is a syntax that indicates that the internal is a regular expression. When entering the relevant regular expression in XML, you only need to enter the content.

Textbox regex validation is not working in uwp

1 Answers1