SPViewStyleCollection class

View styles are defined in \\Program Files\Common Files\Microsoft Shared\Web Server Extensions\12\TEMPLATE\GLOBAL\XML\VWSTYLES.XML.

Use the ViewStyles property of the SPWeb class to return the collection of view styles for a site. Use an indexer to return a single view style from the collection. For example, if the collection is assigned to a variable named collViewStyles, use collViewStyles[index] in C#, or collViewStyles(index) in Visual Basic, where index is the index number of the view style in the collection.

The following code example applies a Boxed style (13) to a view for a list in the specified site.

SPSite oSiteCollection = SPContext.Current.Site;
    using(SPWeb oWebsite = oSiteCollection.AllWebs["Website_Name"])
    {
        SPViewStyleCollection collViewStyles = oWebsite.ViewStyles;

        SPViewStyle oViewStyle = collViewStyles.StyleByID(13);
        SPList oList = oWebsite.Lists["List_Name"];
        SPView oView = oList.Views["View_Name"];
        oView.ApplyStyle(oViewStyle);
        oView.Update();
    }
}

Note
Certain objects implement the IDisposable interface, and you must avoid retaining these objects in memory after they are no longer needed. For information about good coding practices, see Disposing Objects.

Reference