custom validator to check the age entered in the text box

Question

I have a text box on my web page for date of birth. I don't want anyone to enter the age less than 16. if someone enters the age less than 16 than I want to show the error message saying "Less than 16 age is not allowed". I want to write this validation on server side rather than client side script. Below is the date of birth field.

<input onblur="selfservice.dateBlurCallback(event)" data-options="{&quot;mode&quot;:&quot;datebox&quot;,&quot;overrideDateFormat&quot;:&quot;%-m/%-d/%Y&quot;,&quot;lockInput&quot;:false,&quot;usePlaceholder&quot;:&quot;mm/dd/yyyy&quot;,&quot;useModal&quot;:false,&quot;overrideSetDateButtonLabel&quot;:&quot;Set Date&quot;,&quot;showInitialValue&quot;:false,&quot;beforeOpenCallback&quot;:&quot;parseDateCallback&quot;}" name="field_RecordingDateID_DOT_StartDate" id="txtDOB" placeholder="mm/dd/yyyy" type="text" data-role="datebox" value="" runat="server"  ></input>

Below is my customvalidator:

<asp:CustomValidator Display="None" ID="CustomValidator1" runat="server" OnServerValidate="ageValidator" ControlToValidate="txtDOB" ErrorMessage=""  />

and below is my server side code:

protected void ageValidator(object source, ServerValidateEventArgs args)
        {
            DateTime dtStart = DateTime.Parse(txtDOB.Value.ToString());
            TimeSpan sp = DateTime.Now - dtStart;

            if (sp.Days < 16 * 365)
            {
                args.IsValid = false;
                CustomValidator1.ErrorMessage = "You have to be at least 16 to order the Certificate";
            }
            else
                args.IsValid = true;
        }

I am not seeing any error message if the date of birth is less than 16. Also, application continues once this method is executed.

any help will be highly appreciated.

Did you try and debug to see if the server-side code is even kicking? — Fandango68, Jul 15 '20 at 01:39
https://stackoverflow.com/questions/5119821/asp-net-custom-validator-not-firing-for-textbox — Fandango68, Jul 15 '20 at 01:40
Ok I see what's happening. The logic is working and you're populating the property of the control, but you;re not displaying. I suggest you need to incorporate an error dialog box in codebehind or javascript to handle exceptions. — Fandango68, Jul 15 '20 at 01:46

score 1 · Accepted Answer · answered Jul 15 '20 at 01:50

You need to include a ValidationSummary control with your asp.net control logic. Even if you populate a property in the CustomValidator control, it makes no sense to just leave it at that point.

Without writing the code entirely out for you, learn about ValidationControls here:

https://www.codeproject.com/articles/20822/custom-validator-and-validation-summary

Here is another excellent example:

https://meeraacademy.com/validationsummary-control-in-asp-net/

custom validator to check the age entered in the text box

1 Answers1