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Getting Started with the DropDownButton

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

You will initialize a DropDownButton control with five items. Next, you will handle the DropDownButton events and display messages in the browser console. Finally, you can run the sample code in Telerik REPL and continue exploring the components.

Sample Telerik UI for ASP.NET Core DropDownButton

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 playground and skip installing the components on your system and configuring a project.

  • You can prepare a Visual Studio project by following ether of these guides:

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:

    @using Kendo.Mvc.UI
    
  • To use the Telerik UI for ASP.NET Core TagHelpers:

    @addTagHelper *, Kendo.Mvc
    

Optionally, you can structure the document by adding the desired HTML elements like headings, divs, paragraphs, and apply some basic styles.

2. Initialize the DropDownButton

Use the DropDownButton 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 DropDownButton element.
  • The Text defines the textual content of the DropDownButton.
    @using Kendo.Mvc.UI

    @(Html.Kendo().DropDownButton()
        .Name("dropDownButton")
        .Text("User Settings"))
    @addTagHelper *, Kendo.Mvc

    <kendo-dropdownbutton name="dropDownButton" text="User Settings">
    </kendo-dropdownbutton>

3. Add the DropDownButton Items

The Items() configuration specifies the items that will be rendered in the DropDownButton.

    @(Html.Kendo().DropDownButton()
        .Name("dropDownButton")
        .Text("User Settings")
        .Items(items=>{
            items.Add().Id("profile").Text("My Profile");
            items.Add().Id("friend-request").Text("Friend Requests");
            items.Add().Id("settings").Text("Account Settings");
            items.Add().Id("support").Text("Support");
            items.Add().Id("logout").Text("Log Out");
        }))
    @addTagHelper *, Kendo.Mvc

    <kendo-dropdownbutton name="dropDownButton" text="User Settings">
        <dropdownbutton-items>
            <item id="profile" text="My Profile"></item>
            <item id="friend-request" text="Friend Requests"></item>
            <item id="settings" text="Account Settings"></item>
            <item id="support" text="Support"></item>
            <item id="logout" text="Log Out"></item>
        </dropdownbutton-items>
    </kendo-dropdownbutton>

3. Configure the Appearance

To alter the appearance of the component, use the ThemeColor and FillMode methods. Additionally, you can also add icons to the DropDownButton and its items.

    @(Html.Kendo().DropDownButton()
        .Name("dropDownButton")
        .Text("User Settings")
        .Icon("user")
        .ThemeColor(ThemeColor.Primary)
        .FillMode(FillMode.Solid)
        .Items(items=>{
            items.Add().Id("profile").Text("My Profile").Icon("image");
            items.Add().Id("friend-request").Text("Friend Requests").Icon("tell-a-friend");
            items.Add().Id("settings").Text("Account Settings").Icon("gear");
            items.Add().Id("support").Text("Support").Icon("question-circle");
            items.Add().Id("logout").Text("Log Out").Icon("logout");
        }))
    @addTagHelper *, Kendo.Mvc

    <kendo-dropdownbutton name="dropDownButton" text="User Settings" theme-color="ThemeColor.Primary" fill-mode="FillMode.Solid" icon="user">
        <dropdownbutton-items>
            <item id="profile" text="My Profile" icon="image"></item>
            <item id="friend-request" text="Friend Requests" icon="tell-a-friend"></item>
            <item id="settings" text="Account Settings" icon="gear"></item>
            <item id="support" text="Support" icon="question-circle"></item>
            <item id="logout" text="Log Out" icon="logout"></item>
        </dropdownbutton-items>
    </kendo-dropdownbutton>

4. Handle DropDownButton Events

The DropDownButton component exposes the Click(), Open(), and Close() events that you can handle and further customize the functionality of the component.

    @(Html.Kendo().DropDownButton()
        .Name("dropDownButton")
        .Text("User Settings")
        .Icon("user")
        .ThemeColor(ThemeColor.Primary)
        .FillMode(FillMode.Solid)
        .Items(items=>{
            items.Add().Id("profile").Text("My Profile").Icon("image");
            items.Add().Id("friend-request").Text("Friend Requests").Icon("tell-a-friend");
            items.Add().Id("settings").Text("Account Settings").Icon("gear");
            items.Add().Id("support").Text("Support").Icon("question-circle");
            items.Add().Id("logout").Text("Log Out").Icon("logout");
        })
        .Events(e=>e.Click("onClick").Open("onOpen").Close("onClose"))
    )

    <script>
        function onClick(e) {
            console.log("event :: click (#" + e.id + ")" );
        }

        function onOpen(e) {
            console.log("event :: open" );
        }

        function onClose(e) {
            console.log("event :: close" );
        }
    </script>
    @addTagHelper *, Kendo.Mvc

    <kendo-dropdownbutton name="dropDownButton" text="User Settings" theme-color="ThemeColor.Primary" fill-mode="FillMode.Solid" icon="user" on-click="onClick" on-open="onOpen" on-close="onClose">
        <dropdownbutton-items>
            <item id="profile" text="My Profile" icon="image"></item>
            <item id="friend-request" text="Friend Requests" icon="tell-a-friend"></item>
            <item id="settings" text="Account Settings" icon="gear"></item>
            <item id="support" text="Support" icon="question-circle"></item>
            <item id="logout" text="Log Out" icon="logout"></item>
        </dropdownbutton-items>
    </kendo-dropdownbutton>

    <script>
        function onClick(e) {
            console.log("event :: click (#" + e.id + ")" );
        }

        function onOpen(e) {
            console.log("event :: open" );
        }

        function onClose(e) {
            console.log("event :: close" );
        }
    </script>

For more examples, refer to the demo on using the events of the DropDownButton.

5. (Optional) Reference Existing DropDownButton Instances

You can reference the DropDownButton 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.

    <script>
        var dropDownButtonReference = $("#dropDownButton").data("kendoDropDownButton"); // dropDownButtonReference is a reference to the existing instance of the helper.
    </script>
    
  2. Use the DropDownButton client-side API to control the behavior of the widget. In this example, you will use the enable method to control the state of the DropDownButton items.

    <script>
        var dropDownButtonReference = $("#dropDownButton").data("kendoDropDownButton"); // dropDownButtonReference is a reference to the existing instance of the helper.
        dropDownButtonReference.enable(false, "#settings"); // Disable the settings item.
    </script>
    

For more information on referencing specific helper instances, see the Methods and Events article.

Explore this Tutorial in REPL

You can continue experimenting with the code sample above by running it in the Telerik REPL server playground:

Next Steps

See Also

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