docs: Add ListView SearchBox KB (#547)

Co-authored-by: Dimo Dimov <dimo@Dimos-MacBook-Pro.local>

Author: dimodi

knowledge-base/listview-searchbox.md

@@ -0,0 +1,125 @@
+---
+title: ListView SearchBox 
+description: How to implement a ListView search box that filters by multiple data fields.
+type: how-to
+page_title: ListView Search Box
+slug: listview-searchbox
+position:
+tags: listview,search,searchbox,filter,filtering
+ticketid: 1536554
+res_type: kb
+---
+
+## Description
+
+How to implement a ListView seach box, similar to the [SearchBox in the Blazor Grid](https://demos.telerik.com/blazor-ui/grid/searchbox)? I would like to use a single input to search and filter in all data fields of the ListView data.
+
+## Solution
+
+It is possible to search and filter the ListView programmatically. The example below is a modified version of the [ListView filtering demo](https://demos.telerik.com/blazor-ui/listview/filtering).
+
+* Notice the usage of a [`CompositeFilterDescriptor`](https://docs.telerik.com/blazor-ui/api/Telerik.DataSource.CompositeFilterDescriptor), instead of a [`FilterDescriptor`](https://docs.telerik.com/blazor-ui/api/Telerik.DataSource.FilterDescriptor). This is because we are searching in multiple fields with an `OR` logical operator. The [Grid Filtering documentation]({%slug components/grid/filtering%}#filter-descriptors) explains the difference between the two descriptor types.
+* Populate the `FilterDescriptors` collection of the `CompositeFilterDescriptor` object with one `FilterDescriptor` for each field that you want to search in.
+
+>caption ListView Search Textbox
+
+````CSHTML
+@* ListView SearchBox *@
+
+@using Telerik.DataSource
+@using Telerik.DataSource.Extensions
+
+<TelerikListView Data="@ListViewData"
+                 Pageable="true"
+                 PageSize="10"
+                 Width="600px">
+    <HeaderTemplate>
+        <div style="padding: 1em">
+            <label for="searchbox">Search in both Name and Descriprtion:</label>
+            <TelerikTextBox Value="@SearchString" ValueChanged="@LoadListViewData"></TelerikTextBox>
+            <TelerikButton OnClick="@ClearSearch">Clear</TelerikButton>
+        </div>
+    </HeaderTemplate>
+    <Template>
+        <div class="listview-box">
+            <strong>@context.Name:</strong>
+            <br />
+            @context.Description
+        </div>
+    </Template>
+</TelerikListView>
+
+<style>
+    .listview-box {
+        display: inline-block;
+        margin: 1em;
+        padding: 1em;
+        border: 1px solid #424242;
+        background: #fafafa;
+    }
+</style>
+
+@code {
+    List<Product> ListViewData;
+    List<Product> SourceData;
+    string SearchString = "22";
+
+    async Task LoadListViewData(string newSearchString)
+    {
+        SearchString = newSearchString;
+
+        if (String.IsNullOrWhiteSpace(SearchString))
+        {
+            ListViewData = SourceData;
+        }
+        else
+        {
+            var request = new DataSourceRequest()
+            {
+                Filters = new List<IFilterDescriptor>()
+            };
+
+            var cfd = new CompositeFilterDescriptor();
+
+            cfd.LogicalOperator = FilterCompositionLogicalOperator.Or;
+            cfd.FilterDescriptors.Add(new FilterDescriptor("Name", FilterOperator.Contains, SearchString));
+            cfd.FilterDescriptors.Add(new FilterDescriptor("Description", FilterOperator.Contains, SearchString));
+
+            request.Filters.Add(cfd);
+
+            ListViewData = (SourceData.ToDataSourceResult(request).Data as IEnumerable<Product>).ToList();
+        }
+    }
+
+    async Task ClearSearch()
+    {
+        SearchString = "";
+        await LoadListViewData(SearchString);
+    }
+
+    protected override async Task OnInitializedAsync()
+    {
+        SourceData = new List<Product>();
+
+        for (int i = 1; i <= 50; i++)
+        {
+
+            SourceData.Add(new Product()
+            {
+                ID = i,
+                Name = "Product " + (i * 11).ToString(),
+                Description = "Description " + (i * 22).ToString()
+            });
+        }
+
+        await LoadListViewData(SearchString);
+    }
+
+    public class Product
+    {
+        public int ID { get; set; }
+        public string Name { get; set; }
+        public string Description { get; set; }
+    }
+}
+````