AutoComplete HtmlHelper Overview

The AutoComplete HtmlHelper extension is a server-side wrapper for the Kendo UI AutoComplete widget.

It enables you to configure the Kendo UI AutoComplete widget from server-side code. The AutoComplete provides suggestions depending on the typed text. It also allows multiple value entries. The suggestions shown by the widget come either from a local array or from a remote data service.

For more information on the HtmlHelper, refer to the article on the AutoComplete HtmlHelper for ASP.NET MVC.

Basic Usage

The following example demonstrates how to define the AutoComplete by using the AutoComplete HtmlHelper.

Example

    @(Html.Kendo().AutoComplete()
        .Name("autocomplete")
        .DataTextField("ProductName")
        .Filter("contains")
        .DataSource(source =>
        {
            source.Read(read =>
            {
                read.Action("Products_Read", "AutoComplete")
                    .Data("onAdditionalData");
            })
            .ServerFiltering(true);
        })
    )

    <script type="text/javascript">
        function onAdditionalData() {
            return {
                text: $("#autocomplete").val()
            };
        }
    </script>

    public class AutoCompleteController : Controller
    {
        public IActionResult Index()
        {
            return View();
        }

        public JsonResult Products_Read(string text)
        {
            var result = GetProducts();

            if (!string.IsNullOrEmpty(text))
            {
                result = result.Where(p => p.ProductName.Contains(text)).ToList();
            }

            return Json(result);
        }

        private static IEnumerable<ProductViewModel> GetProducts()
        {
            var result = Enumerable.Range(0, 50).Select(i => new ProductViewModel
            {
                ProductID = "" + i,
                ProductName = "Product " + i
            });

            return result;
        }
    }

Configuration

The following example demonstrates the basic configuration of the AutoComplete HtmlHelper and how to get the AutoComplete instance.

    @(Html.Kendo().AutoComplete()
        .Name("autocomplete")
        .DataTextField("ProductName")
        .Placeholder("Type a product name")
        .Template("#= ProductID # | For: #= ProductName #")
        .HeaderTemplate("<div class=\"dropdown-header k-widget k-header\">" +
                            "<span>Products</span>" +
                        "</div>")
        .FooterTemplate("Total <strong>#: instance.dataSource.total() #</strong> items found")
        .Filter("contains")
        .MinLength(3)
        .HtmlAttributes(new { style = "width:100%" })
        .Height(520)

        .DataSource(source =>
        {
            source.Read(read =>
            {
                read.Action("Products_Read", "Home")
                    .Data("onAdditionalData");
            })
            .ServerFiltering(true);
        })
        .Events(e => e
        .Change("onChange")
        .Select("onSelect")
        .Open("onOpen")
        .Close("onClose")
        .DataBound("onDataBound")
        .Filtering("onFiltering")
        )
    )

    <script type="text/javascript">
        function onAdditionalData() {
            return {
                text: $("#autocomplete").val()
            };
        }

        $(function () {
            //Notice that the Name() of the AutoComplete is used to get its client-side instance.
            var autocomplete = $("#autocomplete").data("kendoAutoComplete");
            console.log(autocomplete);
        });
    </script>

Model Binding

You can implement model binding both with local data and remote data, and in combination with virtualization.

Local Data

Local data is the data that is available on the client when the AutoComplete is initialized.

1. Pass the data to the view through ViewData.

   Example

       public IActionResult Index()
       {
           ViewData["products"] = GetProducts();
   
           return View(new ProductViewModel
           {
               ProductID = 4,
               ProductName = "ProductName4"
           });
       }
   
       private static IEnumerable<ProductViewModel> GetProducts()
       {
           var products = Enumerable.Range(0, 2000).Select(i => new ProductViewModel
           {
               ProductID = i,
               ProductName = "ProductName" + i
           });
   
           return products;
       }
   

2. Add the AutoComplete to the view and bind it to the data that is saved in ViewData.

   Example

       @model MvcApplication1.Models.ProductViewModel
   
       @(Html.Kendo().AutoCompleteFor(m => m.ProductName)
           .DataTextField("ProductName")
           .BindTo((System.Collections.IEnumerable)ViewData["products"])
       )
   

Remote Data

You can configure the AutoComplete to get its data from a remote source by making an AJAX request.

1. Create an action that returns the data as a JSON result.

   Example

       public IActionResult Index()
       {
           return View(new ProductViewModel
           {
               ProductID = 4,
               ProductName = "ProductName4"
           });
       }
   
       public JsonResult GetProductsAjax()
       {
           var products = Enumerable.Range(0, 500).Select(i => new ProductViewModel
           {
               ProductID = i,
               ProductName = "ProductName" + i
           });
   
           return Json(products);
       }
   

2. Add the AutoComplete to the view and configure its DataSource to use remote data.

   Example

       @model MvcApplication1.Models.ProductViewModel
   
   
       @(Html.Kendo().AutoCompleteFor(m => m.ProductName)
           .Filter("contains")
           .DataTextField("ProductName")
           .Placeholder("Select product...")
           .DataSource(source =>
           {
               source.Read(read =>
               {
                   read.Action("GetProductsAjax", "Home");
               })
               .ServerFiltering(false);
           })
       )
   

Virtualization

You can configure an AutoComplete that is bound to a model field to use virtualization.

Important

The value type to which the AutoComplete can be bound on the server can only be a primitive type or an enum value.

1. Create the Read and ValueMapper actions.

   Example

       public IActionResult Index()
       {
           return View(new ProductViewModel
           {
               ProductID = 4,
               ProductName = "ProductName4"
           });
       }
   
       [HttpPost]
       public IActionResult ProductsVirtualization_Read([DataSourceRequest] DataSourceRequest request)
       {
           return Json(GetProducts().ToDataSourceResult(request));
       }
   
       public IActionResult Products_ValueMapper(int[] values)
       {
           var indices = new List<int>();
   
           if (values != null && values.Any())
           {
               var index = 0;
   
               foreach (var product in GetProducts())
               {
                   if (values.Contains(product.ProductID))
                   {
                       indices.Add(index);
                   }
   
                   index += 1;
               }
           }
   
           return Json(indices);
       }
   
       private static IEnumerable<ProductViewModel> GetProducts()
       {
           var products = Enumerable.Range(0, 2000).Select(i => new ProductViewModel
           {
               ProductID = i,
               ProductName = "ProductName" + i
           });
   
           return products;
       }
   

2. Add the AutoComplete to the view and configure it to use virtualization.

   Example

       @model MvcApplication1.Models.ProductViewModel
   
       @(Html.Kendo().AutoCompleteFor(m => m.ProductName)
           .Filter("contains")
           .DataTextField("ProductName")
           .DataSource(source =>
           {
               source.Custom()
                   .ServerFiltering(true)
                   .ServerPaging(true)
                   .PageSize(80)
                   .Type("aspnetmvc-ajax")
                   .Transport(transport =>
                   {
                       transport.Read("ProductsVirtualization_Read", "Home");
                   })
                   .Schema(schema =>
                   {
                       schema.Data("Data")
                               .Total("Total");
                   });
           })
           .Virtual(v => v.ItemHeight(26).ValueMapper("valueMapper"))
       )
   
   
       <script>
           function valueMapper(options) {
               $.ajax({
                   url: "@Url.Action("Products_ValueMapper", "Home")",
                   data: convertValues(options.value),
                   success: function (data) {
                       options.success(data);
                   }
               });
           }
   
           function convertValues(value) {
               var data = {};
   
               value = $.isArray(value) ? value : [value];
   
               for (var idx = 0; idx < value.length; idx++) {
                   data["values[" + idx + "]"] = value[idx];
               }
   
               return data;
           }
       </script>
   

See Also

• JavaScript API Reference of the AutoComplete
• AutoComplete HtmlHelper for ASP.NET MVC
• AutoComplete Official Demos
• Overview of Telerik UI for ASP.NET Core
• Get Started with Telerik UI for ASP.NET Core in ASP.NET Core Projects
• Get Started with Telerik UI for ASP.NET Core in ASP.NET Core Projects with the CLI
• Known Issues with Telerik UI for ASP.NET Core