Added new kb article combobox-prevent-numeric

knowledge-base/combobox-prevent-numeric.md

@@ -0,0 +1,65 @@
+---
+title: How to Restrict Numeric Input in ComboBox
+description: Learn how to prevent users from typing numbers in a Telerik UI for Blazor ComboBox.
+type: how-to
+page_title: How to Prevent Numeric Input in Blazor ComboBox
+slug: combobox-kb-prevent-numeric
+tags: combobox, blazor, input, numeric
+res_type: kb
+ticketid: 1682510
+---
+
+## Environment
+
+<table>
+	<tbody>
+		<tr>
+			<td>Product</td>
+			<td>ComboBox for Blazor</td>
+		</tr>
+	</tbody>
+</table>
+
+## Description
+
+I want to restrict typing numbers in the [`ComboBox`](slug:components/combobox/overview) component.
+
+## Solution
+
+To prevent users from entering numbers in the ComboBox: 
+
+1. Wrap the component in an HTML element and use the `onkeydown` event to capture every keystroke.
+2. Implement a JavaScript function that prevents the numbers.
+
+Below is the implementation:
+
+`````Razor
+<div onkeydown="preventNumbers(event)">
+    <TelerikComboBox Data="@ComboData"
+                     Value="@ComboValue"
+                     ValueChanged="@( (string newValue) => OnComboValueChanged(newValue) )"
+                     Width="300px">
+    </TelerikComboBox>
+</div>
+
+<script suppress-error="BL9992">
+    function preventNumbers(event) {
+        if (event.key >= '0' && event.key <= '9') {
+            event.preventDefault();
+        }
+    }
+</script>
+
+@code {
+    private string? ComboValue { get; set; }
+
+    private List<string> ComboData { get; set; } = new List<string> {
+        "Manager", "Developer", "QA", "Technical Writer", "Support Engineer"
+    };
+
+    private void OnComboValueChanged(string newValue)
+    {
+        ComboValue = newValue;
+    }
+}
+`````