kb(grid):search in hidden fields

components/grid/filter/searchbox.md

@@ -73,7 +73,7 @@ The `GridSearchBox` component offers the following settings to customize its beh
 
 * `DebounceDelay` - the time in `ms` with which the typing is debounced. This provides a performance optimization when using the `OnRead` event - filtering does not happen on every keystroke anymore. The default value is `300`.
 
-* `Fields` - a list of `string` that denotes the fields names that the grid should search in. By default, the grid looks in all string fields in its currently visible columns, and you can define a subset of that.
+* `Fields` - a `List<string>` that includes the fields names that the Grid should search in. By default, the Grid searches in all string fields, which are bound to visible columns. You can only define a subset of those fields. It is also possible to programmatically [search in string fields, which are not displayed in the Grid]({%slug grid-kb-search-in-hidden-fields%}).
 
 * `Class` - a CSS class rendered on the wrapper of the searchbox so you can customize its appearance.
 

knowledge-base/grid-search-in-hidden-fields.md

@@ -0,0 +1,115 @@
+---
+title: Search in hidden fields of the Grid
+description: How to search in hidden fields of the Grid?
+type: how-to
+page_title: Search in hidden fields of the Grid
+slug: grid-kb-search-in-hidden-fields
+position: 
+tags: telerik,blazor,grid,search,searchbox,hidden,field,column,not,visible
+ticketid: 1540910
+res_type: kb
+---
+
+## Environment
+<table>
+	<tbody>
+		<tr>
+			<td>Product</td>
+			<td>Grid for Blazor</td>
+		</tr>
+	</tbody>
+</table>
+
+
+## Description
+
+I want to customize the Grid Toolbar Searchbox, so it also searches in the hidden fields of the Grid and not only in the visible ones. How to achieve that?
+
+## Solution
+
+By default, the Grid looks in all string fields in its currently visible columns. You can [customize the SearchBox]({%slug grid-searchbox%}#customize-the-searchbox), so the Grid will search only in certain columns. However, the search will still be based on the **visible** fields provided to the `Fields` parameter of the `GridSearchBox`.
+
+If you want to search in the hidden fields of the Grid, do the following:
+
+* Use the Grid with an [OnRead handler]({%slug components/grid/manual-operations%}).
+* In the OnRead handler, [check if there is a filter applied]({%slug components/grid/manual-operations%}#get-information-from-the-datasourcerequest).
+* The applied filter must be of type [CompositeFilterDescriptor](https://docs.telerik.com/blazor-ui/api/Telerik.DataSource.CompositeFilterDescriptor). Plain `FilterDescriptors` at root level (`args.Request.Filters`) are generated by the filter row. The composite filter descriptor has a `FilterDescriptors` property, which holds a collection plain [single-field FilterDescriptors](https://docs.telerik.com/blazor-ui/api/Telerik.DataSource.FilterDescriptor). Each of them targets one of the visible columns.
+* Obtain the search string from the `Value` property of any of the descriptors in the above collection.
+* Add one additional `FilterDescriptor` to the above collection that targets the hidden column.
+
+Here is an example:
+
+````CSHTML
+@using Telerik.DataSource.Extensions
+@using Telerik.DataSource
+
+<TelerikGrid Data="@CurrentGridData" TotalCount="@CurrentGridTotalCount"
+             OnRead="@GridReadHandler"
+             FilterMode="@GridFilterMode.FilterRow">
+    <GridToolBar>
+        <strong style="color:#900">Search for "secret#", where # is the ID number:</strong>
+        <span class="k-toolbar-spacer"></span>
+        <GridSearchBox DebounceDelay="200"></GridSearchBox>
+    </GridToolBar>
+    <GridColumns>
+        <GridColumn Field="@nameof(GridItem.ID)" />
+        <GridColumn Field="@nameof(GridItem.Name)" />
+        <GridColumn Field="@nameof(GridItem.Secret)" Visible="false" />
+    </GridColumns>
+</TelerikGrid>
+
+@code {
+
+    private int CurrentGridTotalCount { get; set; }
+
+    public List<GridItem> GridData { get; set; } = new List<GridItem>();
+    public List<GridItem> CurrentGridData { get; set; } = new List<GridItem>();
+
+    protected override Task OnInitializedAsync()
+    {
+        for (int j = 1; j <= 9; j++)
+        {
+            GridData.Add(new GridItem() { ID = j, Name = "Name " + j, Secret = "Secret" + j });
+        }
+
+        return base.OnInitializedAsync();
+    }
+
+    private async Task GridReadHandler(GridReadEventArgs args)
+    {
+        // check if we have any filtering at all
+        if (args.Request.Filters.Count > 0)
+        {
+            foreach (var rootFilterDescriptor in args.Request.Filters)
+            {
+                // row filters are FilterDescriptors; search and menu filters are CompositeFilterDescriptors
+                if (rootFilterDescriptor.GetType() == typeof(CompositeFilterDescriptor))
+                {
+                    var searchDescriptor = rootFilterDescriptor as CompositeFilterDescriptor;
+                    var searchString = (searchDescriptor.FilterDescriptors[0] as FilterDescriptor).Value.ToString();
+
+                    // add a descriptor for each hidden column that you want to search in
+                    searchDescriptor.FilterDescriptors.Add(new FilterDescriptor()
+                    {
+                        Member = "Secret",
+                        MemberType = typeof(string),
+                        Value = searchString,
+                        Operator = FilterOperator.Contains
+                    });
+                }
+            }
+        }
+
+        var result = GridData.ToDataSourceResult(args.Request);
+        CurrentGridData = (result.Data as IEnumerable<GridItem>).ToList();
+        CurrentGridTotalCount = result.Total;
+    }
+
+    public class GridItem
+    {
+        public int ID { get; set; }
+        public string Name { get; set; }
+        public string Secret { get; set; }
+    }
+}
+````