Creating a Configurable Dropdown Using UI Snippets in Web Dynpro 
You use this procedure to create a configurable dropdown using the available UI snippets in Web Dynpro. You can generate values in the dropdown UI element as follows:
Create a context attribute of Dictionary type that has a default set of enumeration values associated with it.
Insert your code in the user code area of the Java editor based on your business logic.
Prerequisites
You have created a Web Dynpro development component (DC).
For more information, see Creating a Web Dynpro DC
You have created a Web Dynpro component, window, and views.
For more information, see Creating Components
You have created an additional window.
For more information, see Adding Windows
You have created a context.
For more information, see Creating Context Trees Manually
Procedure
In the Web Dynpro perspective, choose
Windows 
Show Views Snippets 
.Drag the Configurable Drop Down snippet, and drop it on the View Designer.
In the Insert Snippet: Configurable Drop Down, select the suitable attribute from the context tree and choose Insert.
The system creates a dropdown on the View Designer.
Note
The system displays the values in the dropdown at runtime either from enumeration values that have the predefined set of values or from the inserted code based on the business logic you have defined.