Sample : http://code.msdn.microsoft.com/How-to-use-DropDownList-1961c60e
ASP.NET MVC 4 is a framework for building scalable, standards-based web applications using well-established design patterns and the power of ASP.NET and the .NET Framework. This article and the attached code samples demonstrate demonstrates how to use cascading dropdown list with ASP.NET MVC 4. You can find the answers for all the following questions in the code sample:
• How to create a simple dropdown list
• How to post data to server when dropdown list selected item changed
• How to implement cascaded DropDownList
• How to update the local section accroding to the item selected
• How to dynamically generate options for dropdown list
You can find more code samples that demonstrate the most typical programming scenarios by using Microsoft All-In-One Code Framework Sample Browser or Sample Browser Visual Studio extension. They give you the flexibility to search samples, download samples on demand, manage the downloaded samples in a centralized place, and automatically be notified about sample updates. If it is the first time that you hear about Microsoft All-In-One Code Framework, please watch the introduction video on Microsoft Showcase, or read the introduction on our homepage http://1code.codeplex.com/.