RadComboBox provides many built-in features which can be enabled using a single property. You can find a detailed list of the available configuration options and their respective descriptions here:

RadComboBox API Reference

This article provides a summary of the most popular events used in real business cases. Default inherited events like Init, Load and PreRender are not mentioned explicitly since they do not provide additional custom arguments like the other events do. However, they still can have their place in some implementations.

Events

RadComboBox supports a number of server-side events that let you respond to events with complex actions that can't be performed in client-side code.

  • ItemsRequested occurs when the load-on-demand mechanism needs to add items to the combobox.

  • ItemCreated occurs when a new item is added to the Items collection.

  • ItemDataBound occurs for each item when it is being bound to a data value.

  • SelectedIndexChanged occurs when the selected item has just changed.

  • TextChanged occurs when the text in the input area has been changed.

  • ItemChecked occurs when a checkbox is checked/unchecked.

  • CheckAllCheck occurs when the check all items check box is changed.

The SelectedIndexChanged , TextChanged and OnCheckAllCheck events do not fire unless you set the AutoPostBack property to True .

Practical Use of the Individual Events

Although every event has its own dedicated article, in this section you can find a summary for their practical usage.

Data-binding

Usually, in every day applications, the combo components do not have so many options to choose from. But in some cases they need to present the user with a lot of choices. In these scenarios the developer can choose to use the EnableLoadOnDemand or EnableAutomaticLoadOnDemand features. And ItemsRequested comes into play right at this place.

The ItemDataBound event is similar to the other controls. It is raised for every item of the combo and you can then execute custom logic per every option. Usually, this includes some type of conditional statements.

And while the ItemDataBound event is raised only while databinding, ItemCreated on the other hand is raised on every regular PostBack action which can have its use in some scenarios.

Value Change

The default event here is the one and only SelectedIndexChanged. However, when the AllowCustomText property (or other similar feature which enforces this property) is switched on, you can also make avail of the TextChanged event.

CheckBox Events

RadComboBox also provides built-in CheckBoxes functionality. They also have their related events. ItemChecked corresponds and is raised when the user checks a single item, while the CheckAllCheck is raised when the top CheckBox is checked to mark all of the combobox options.

See Also

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