How can we switch views of the list which is created on visual studio? SharePoint designer solution or code solution?
If you have created a List Definition from visual studio you can open the Schema.xml and modify the views, this Msdn documentation shows you how: http://msdn.microsoft.com/en-us/library/ms459356(v=office.14).aspx
It is also possible modify views directly in the GUI : http://office.microsoft.com/en-us/sharepoint-foundation-help/create-modify-or-delete-a-view-HA010377693.aspx
If you are talking about showing a control for changing views in the GUI you should get that control OOTB when you add a list view web part, otherwise look in to the list view selector control: http://msdn.microsoft.com/en-us/library/microsoft.sharepoint.webcontrols.listviewselector.aspx