Developers always try to provide the user a easiest way to represent the data irrespective of the technology that has been used. Hence, for a huge collection of data, generally we provide “AutoComplete TextBox” to the user instead of ComboBox or ListBox. The reason behind this is to provide searchable and filterable UI to the user for easy access. Today in this post, we will learn how to use the Telerik’s RadAutoCompleteBox in both Silverlight and Windows Phone. More or less we all know about AutoCompleteBox and how it works. But in this post, we will see the Telerik’s RadControls library to use the AutoCompleteBox and the difference between Silverlight and Windows Phone APIs. Telerik’s RadAutoCompleteBox is present in the “Telerik.Windows.Controls.Input.dll” under the “Telerik.Windows.Controls” namespace and provides the user easy way to access the data in a searchable and filterable mode.