Added new kb article grid-autoexpand-filter-section-column-menu (#3407)

Co-authored-by: KB Bot <kb-bot@telerik.com>

Author: kendo-bot

knowledge-base/grid-autoexpand-filter-section-column-menu.md

@@ -0,0 +1,101 @@
+---
+title: Automatically Expand Filter Section in Grid Column Menu
+description: Learn how to auto-expand the filter section when opening the column menu in TelerikGrid.
+type: how-to
+page_title: Automatically Expand Filter Section in Grid Column Menu
+meta_title: Autoexpand Filter Section in Grid Column Menu
+slug: grid-kb-autoexpand-filter-section-column-menu
+tags: grid, column-menu, filter
+res_type: kb
+ticketid: 1705448
+---
+
+## Environment
+
+<table>
+    <tbody>
+        <tr>
+            <td>Product</td>
+            <td>Grid for Blazor</td>
+        </tr>
+    </tbody>
+</table>
+
+## Description
+
+I want the filter section of the [column menu](slug:grid-column-menu) in the [TelerikGrid](slug:grid-overview) to automatically open when a user opens the column menu. 
+
+## Solution
+
+To auto-expand the filter section, use JavaScript interop to simulate a click on the filter header when the column menu is opened. Below is a runnable example:
+
+````Razor
+@inject IJSRuntime JSRuntime
+
+<TelerikGrid Data="@GridData"
+             Pageable="true"
+             PageSize="5"
+             FilterMode="@GridFilterMode.FilterMenu"
+             Sortable="true"
+             ShowColumnMenu="true">
+    <GridColumns>
+        <GridColumn Field="@(nameof(SampleData.Id))" Width="80px" />
+        <GridColumn Field="@(nameof(SampleData.Name))" Title="Employee Name" Groupable="false" />
+        <GridColumn Field="@(nameof(SampleData.Team))" Title="Team" />
+        <GridColumn Field="@(nameof(SampleData.HireDate))" Title="Hire Date" />
+    </GridColumns>
+</TelerikGrid>
+
+<script>
+        window.initColumnMenuAutoClick = function () {
+        // Select all column menu buttons in the grid header
+        const menuButtons = document.querySelectorAll(".k-grid .k-header .k-grid-column-menu");
+
+        menuButtons.forEach(btn => {
+            btn.addEventListener("click", () => {
+                // Wait for the popup animation (adjust timeout if needed)
+                setTimeout(() => {
+                    const items = document.querySelectorAll(
+                        ".k-column-menu .k-columnmenu-item-wrapper .k-columnmenu-item"
+                    );
+
+                    items[3].click();
+                }, 150); // Adjust if animation is slower/faster
+            });
+        });
+    };
+
+</script>
+
+@code {
+    protected override async Task OnAfterRenderAsync(bool firstRender)
+    {
+        if (firstRender)
+        {
+            await Task.Delay(500); // Ensure the grid is fully rendered
+            await JSRuntime.InvokeVoidAsync("initColumnMenuAutoClick");
+        }
+    }
+
+    private IEnumerable<SampleData> GridData = Enumerable.Range(1, 30).Select(x => new SampleData
+    {
+        Id = x,
+        Name = "name " + x,
+        Team = "team " + x % 5,
+        HireDate = DateTime.Now.AddDays(-x).Date
+    });
+
+    public class SampleData
+    {
+        public int Id { get; set; }
+        public string Name { get; set; }
+        public string Team { get; set; }
+        public DateTime HireDate { get; set; }
+    }
+}
+````
+
+## See Also
+
+* [Grid Documentation](slug:grid-overview)
+* [Column Menu Documentation](slug:grid-column-menu)