custom page as default page

using (SPSite oSiteCollection = new SPSite("http://MyServer/sites/MyWikiSite"))
{
    SPWeb oWebsite = oSiteCollection.OpenWeb();
    SPFolder oFolder = oWebsite.RootFolder; 
    oFolder.WelcomePage = "My Wiki Library/MyWelcome.aspx";
    oFolder.Update();
    oWebsite.Dispose();
}