Validator TagHelper Overview

The Telerik UI Validator TagHelper for ASP.NET Core is a server-side wrapper for the Kendo UI Validator widget.

The Validator offers options for implementing client-side form validation.

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Initializing the Validator

The following example demonstrates how to define the Validator by using the Validator TagHelper.

        var messages = new Dictionary<string, string>() { { "custom", "Please choose another Start Time." } };
        var rules = new Dictionary<string, string>() { { "custom", "customFunction" } };
    <form id="ticketsForm" kendo-validator="true" kendo-messages="messages" kendo-rules="rules">
        <ul id="fieldlist">
                <label for="fullname" class="required">Your Name</label>
                    .HtmlAttributes(new { placeholder = "Full name", required = "required", style = "width:220px" })
        function customFunction(input) {

            if (input.attr('name') === "time" && input.val() == "14:00") {
                return false;

            return true;

        $(document).ready( function () {
            var validator = $("#ticketsForm").data("kendoValidator");
            var validationSummary = $("#validation-summary");

            $("form").submit(function(event) {

                if (validator.validate()) {
                    validationSummary.html("<div class='k-messagebox k-messagebox-success'>Hooray! Your tickets has been booked!</div>");
                } else {
                    validationSummary.html("<div class='k-messagebox k-messagebox-error'>Oops! There is invalid data in the form.</div>");

See Also

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