Merge new-kb-multiselect-limit-selection-c8fda6ffa4544544bee101b95debb591-2543 into production (#2567)

* Added new kb article multiselect-limit-selection

* kb(MultiSelect): apply suggestions and improve example

---------

Co-authored-by: KB Bot <[email protected]>
Co-authored-by: Tsvetomir Hristov <[email protected]>

Author: 3 people

knowledge-base/multiselect-limit-selection.md

@@ -0,0 +1,76 @@
+---
+title: Restrict the Number of Selected Items in the MultiSelect
+description: Learn how to restrict the number of selectable items in the Telerik Blazor MultiSelect component.
+type: how-to
+page_title: How to Restrict the Number of Selected Items in MultiSelect for Blazor
+slug: multiselect-kb-limit-selection
+tags: multiselect, blazor, selection limit
+res_type: kb
+ticketid: 1670731
+---
+
+## Environment
+
+<table>
+    <tbody>
+        <tr>
+            <td>Product</td>
+            <td>MultiSelect for Blazor</td>
+        </tr>
+    </tbody>
+</table>
+
+## Description
+
+When using the [MultiSelect]({%slug multiselect-overview%}) component, it might be necessary to limit the number of items a user can select. For example, restricting selection to a maximum of three items. This KB article also answers the following questions:
+- How to set a selection limit on MultiSelect in Blazor?
+- How to prevent additional selections in MultiSelect after reaching a defined limit?
+- How to notify users they've reached the maximum number of selectable items in MultiSelect?
+
+## Solution
+
+To restrict the number of selectable items in a MultiSelect component, use one-way binding with the `Value` parameter and the [`ValueChanged`]({%slug multiselect-events%}#valuechanged) event. This approach allows you to manually update the selected items collection and enforce a maximum selection limit.
+
+Below is a demonstration of how to implement a selection limit. This example restricts the user to a maximum of three selections and informs them when they have reached this limit.
+
+````CSHTML
+<TelerikMultiSelect Data="@MultiData"
+                    Value="@MultiValues"
+                    ValueChanged="@( (List<string> newValues) => OnMultiValueChanged(newValues) )"
+                    AutoClose="false"
+                    OnItemRender="@OnItemRenderHandler"
+                    Width="400px">
+</TelerikMultiSelect>
+
+@if (MultiValues.Count == 3)
+{
+    <span style="color:red;">Maximum  selected items reached</span>
+}
+
+@code {
+    private static List<string> MultiData { get; set; } = new List<string> {
+        "Manager", "Developer", "QA", "Technical Writer", "Support Engineer", "Software Architect", "Product Manager"
+    };
+    private List<string> MultiValues { get; set; } = new List<string>() { MultiData[0] };
+
+    private void OnItemRenderHandler(MultiSelectItemRenderEventArgs<string> args)
+    {
+        if (MultiValues.Count == 3 && !MultiValues.Contains(args.Item))
+        {
+            args.Class = "k-disabled";
+        }
+    }
+    private void OnMultiValueChanged(List<string> newValues)
+    {
+        if (newValues.Count <= 3)
+        {
+            MultiValues = newValues;
+        }
+    }
+}
+````
+
+## See Also
+
+- [MultiSelect Overview]({%slug multiselect-overview%})
+- [MultiSelect Events]({%slug multiselect-events%})