Added new kb article grid-display-active-filters-above-grid (#638)

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

Author: github-actions[bot]

knowledge-base/grid-display-active-filters-above-grid.md

@@ -0,0 +1,92 @@
+---
+title: Display Active Filters Above Grid
+description: Learn how to show which columns are being filtered in a RadGrid control and the specific filter values applied to each column.
+type: how-to
+page_title: Display Active Filters Above Grid
+slug: grid-display-active-filters-above-grid
+tags: radgrid, asp.net ajax, filtering, display, columns, values
+res_type: kb
+ticketid: 1672360
+---
+
+## Environment
+
+<table>
+<tbody>
+<tr>
+<td>Product</td>
+<td>RadGrid for ASP.NET AJAX</td>
+</tr>
+<tr>
+<td>Version</td>
+<td>All</td>
+</tr>
+</tbody>
+</table>
+
+## Description
+
+I need to display the active filters applied to a RadGrid control, including both the columns being filtered and the specific values used for filtering. The filtered columns and their respective values should be shown in a label above the control.
+
+This knowledge base article also answers the following questions:
+
+- How can I display the columns that are currently being filtered in a RadGrid?
+- How do I show the filter values for each filtered column in a RadGrid?
+- What method can be used to list active filters in a RadGrid control?
+
+## Solution
+
+To display the filtered columns and their corresponding filter values above a RadGrid control, follow these steps:
+
+1. Loop through each column in the RadGrid to check if it is being filtered.
+2. For columns with active filters, retrieve the filter value and function.
+3. Concatenate the collected filter details into a readable format.
+4. Display this information in a label or another suitable control placed above the RadGrid.
+
+Here is a code example that demonstrates this approach:
+
+````ASP.NET
+<asp:Label Text="lblFilterDetails" ID="lblFilterDetails" runat="server" />
+<telerik:RadGrid ID="RadGrid1" runat="server" AllowPaging="True" Width="800px" OnPreRender="RadGrid1_PreRender" 
+    AllowFilteringByColumn="true" OnNeedDataSource="RadGrid1_NeedDataSource">
+    <MasterTableView AutoGenerateColumns="False" DataKeyNames="OrderID">
+        <Columns>
+            <!-- Define your RadGrid columns here -->
+        </Columns>
+    </MasterTableView>
+</telerik:RadGrid>
+````
+
+````C#
+protected void RadGrid1_PreRender(object sender, EventArgs e)
+{
+    List<string> filterDetails = new List<string>();
+
+    foreach (GridColumn column in RadGrid1.MasterTableView.RenderColumns)
+    {
+        if (!string.IsNullOrEmpty(column.CurrentFilterValue))
+        {
+            string filteredColumn = column.UniqueName;
+            string filterFunction = column.CurrentFilterFunction.ToString();
+            string filterValue = column.CurrentFilterValue;
+
+            string filterInfo = string.Format("Filtering column {0} with filter function {1} and value {2}", filteredColumn, filterFunction, filterValue);
+
+            filterDetails.Add(filterInfo);
+        }
+    }
+
+    lblFilterDetails.Text = filterDetails.Count > 0 ? "Filtered Columns: " + string.Join(", ", filterDetails) : "No filters applied.";
+}
+````
+
+### Explanation
+- **RadGrid1_PreRender**: This event ensures that the filter information is retrieved after filtering is applied.
+- **filterDetails**: A list that holds the filter details for each filtered column.
+- **lblFilterDetails**: The control used to display the active filter information above the RadGrid.
+
+By following this solution, you can effectively display the filtered columns along with their filter functions and values, helping users understand how the data is being filtered.
+
+## See Also
+
+- [RadGrid Filtering Overview](https://www.telerik.com/products/aspnet-ajax/documentation/controls/grid/functionality/filtering/overview)