# Getting Started with the OTPInput

This tutorial explains how to set up a basic Telerik UI for ASP.NET Core OTPInput component and highlights the major steps in the configuration of the component.

You will initialize an OTPInput component with a set of items. Which will be either grouped together or rendered as standalone OTPInputs. This gives you control over the component's input composition.

Then, you will use the events of the UI component. Finally, you can run the sample code in [Telerik REPL](https://netcorerepl.telerik.com/) and continue exploring the components.

![Sample Telerik UI for ASP.NET Core OTPInput](https://www.telerik.com/aspnet-core-ui/documentation/assets/34849e316343148a48351b24a3338ba5/otpinput-getting-started.png)

## Prerequisites

To successfully complete the tutorial, you need a project that is already configured to use the Telerik UI for ASP.NET Core components:

* You can use the [Telerik REPL](https://netcorerepl.telerik.com/) playground and skip installing the components on your system and configuring a project.

* You can prepare a Visual Studio project by following the following guide:

  * Creating a new pre-configured project for the Telerik UI for ASP.NET Core components from [a project template](https://www.telerik.com/aspnet-core-ui/documentation/vs-integration/new-project-wizard).

## 1. Prepare the CSHTML File

The first step is to add the required directives at the top of the `.cshtml` document:

* To use the Telerik UI for ASP.NET Core HtmlHelpers:

  ```cshtml
  @using Kendo.Mvc.UI
  ```

* To use the Telerik UI for ASP.NET Core TagHelpers:

  ```cshtml
  @addTagHelper *, Kendo.Mvc
  ```

Optionally, you can structure the document by adding the desired HTML elements like headings, divs, paragraphs, and others.

```Razor HtmlHelper
    @using Kendo.Mvc.UI

    <h4>OTPInput with Predefined Items</h4>
    <br/>
    <div>

    </div>
```

```Razor TagHelper
    @addTagHelper *, Kendo.Mvc

    <h4>OTPInput with Predefined Items</h4>
    <br/>
    <div>

    </div>
```

## 2. Initialize the OTPInput

Use the OTPInput HtmlHelper or TagHelper to add the component to a page:

* The `Name()` configuration method is mandatory as its value is used for the `id` and the `name` attributes of the OTPInput element.
* The `Items()` collection contains the list of items representing the different input groups.
* The `Space()` configuration controls the spacing behavior between each of the input groups.

```Razor HtmlHelper
    @using Kendo.Mvc.UI

    <h4>OTPInput with Predefined Items</h4>
    <br/>
    <div>
        @(Html.Kendo().OTPInput()
                .Name("otp")
                .Items(items => {
                    items.Add().GroupLength(3);
                    items.Add().GroupLength(2);
                    items.Add().GroupLength(3);
                })
                .Space(false)
        )
    </div>
```

```Razor TagHelper
    @addTagHelper *, Kendo.Mvc

    <h4>OTPInput with Predefined Items</h4>
    <br/>
    <div>
        <kendo-otpinput name="otp" space="false">
                <otpinput-items>
                    <item group-length="3" />
                    <item group-length="2" />
                    <item group-length="3" />
                </otpinput-items>
         </kendo-otpinput>
    </div>
```

## 3. Configure the Separator

The OTPInput components allows you to add a separator between each of the established input groups. In this tutorial, you will use the available `SeparatorHandler()` option to render an [SVG Icon](https://docs.telerik.com/aspnet-core/styles-and-layout/sass-themes/svg-icons#what-are-svg-icons).

```Razor HtmlHelper
    @using Kendo.Mvc.UI

    <h4>OTPInput with Predefined Items</h4>
    <br/>
    <div>
        @(Html.Kendo().OTPInput()
                .Name("otp")
                .Items(items => {
                    items.Add().GroupLength(3);
                    items.Add().GroupLength(2);
                    items.Add().GroupLength(3);
                })
                .Space(false)
                .SeparatorHandler("separatorHandler")
        )
    </div>
```

```Razor TagHelper
    @addTagHelper *, Kendo.Mvc

    <h4>OTPInput with Predefined Items</h4>
    <br/>
    <div>
        <kendo-otpinput name="otp"
                        space="false"
                        separator-handler="separatorHandler">
                <otpinput-items>
                    <item group-length="3" />
                    <item group-length="2" />
                    <item group-length="3" />
                </otpinput-items>
         </kendo-otpinput>
    </div>
```

```JavaScript
    <script>
        function separatorHandler(e) {
            return kendo.ui.icon({icon: "minus", type:"svg"});
        }
    </script>
```

## 4. Handle an OTPInput Event

The OTPInput component provides a convenient event for implementing your desired logic. In this tutorial, you will use the exposed `Change()` event to log a new entry in the browser's console.

```Razor HtmlHelper
    @using Kendo.Mvc.UI

    <h4>OTPInput with Predefined Items</h4>
    <br/>
    <div>
       @(Html.Kendo().OTPInput()
           .Name("otp")
           .Items(items => {
               items.Add().GroupLength(3);
               items.Add().GroupLength(2);
               items.Add().GroupLength(3);
           })
           .Space(false)
           .SeparatorHandler("separatorHandler")
           .Events(events => events.Change("onChange"))
       )
    </div>
```

```Razor TagHelper
    @addTagHelper *, Kendo.Mvc

    <h4>OTPInput with Predefined Items</h4>
    <br/>
    <div>
        <kendo-otpinput name="otp" 
                        space="false"
                        separator-handler="separatorHandler"
                        on-change="onChange">
             <otpinput-items>
                 <item group-length="3" />
                 <item group-length="2" />
                 <item group-length="3" />
             </otpinput-items>
        </kendo-otpinput>
    </div>
```

```JavaScript
    <script>
       function onChange(e) {
          console.log("Change :: " + e.value);
       }

       function separatorHandler(e) {
            return kendo.ui.icon({icon: "minus", type:"svg"});
       }
    </script>
```

## 5. (Optional) Reference Existing OTPInput Instances

You can reference the OTPInput instances that you have created and build on top of their existing configuration:

1. Use the `id` attribute of the component instance to establish a reference.

   ```JS script
   <script>
       var otpinputReference = $("#otpinput").getKendoOTPInput(); // otpinputReference is a reference to the existing OTPInput instance of the helper.
   </script>
   ```

2. Use the [OTPInput client-side API](https://docs.telerik.com/kendo-ui/api/ui/otpinput#methods) to control the behavior of the widget. In this example, you will use the `enable` method to disable the OTPInput.

   ```JS script
   <script>
        var otpinputReference = $("#otpinput").getKendoOTPInput(); // otpinputReference is a reference to the existing OTPInput instance of the helper.
        otpinputReference.enable(false); 
   </script>
   ```

## Next Steps

* [Customize the Type of the OTPInput](https://www.telerik.com/aspnet-core-ui/documentation/html-helpers/editors/otpinput/types)
* [Configure the Appearance of the OTPInput](https://www.telerik.com/aspnet-core-ui/documentation/html-helpers/editors/otpinput/appearance)

## See Also

* [Using the API of the OTPInput for ASP.NET Core (Demo)](https://demos.telerik.com/aspnet-core/otpinput/api)

* [Server-Side API of the OTPInput HtmlHelper](https://www.telerik.com/aspnet-core-ui/documentation/api/otpinput)

* [Server-Side API of the OTPInput TagHelper](https://www.telerik.com/aspnet-core-ui/documentation/api/taghelpers/otpinput)

* [Client-Side API of the OTPInput](https://docs.telerik.com/kendo-ui/api/ui/otpinput)

* [Knowledge Base Section](https://www.telerik.com/aspnet-core-ui/documentation/knowledge-base)