Sharepoint Website Collection.

Listing all the websites from the share point site and its owner.

SPSite site = new SPSite("http://localhost");
SPWeb web=site.AllWebs;
foreach(SPWeb web in collection)
        {
            DropDownList1.Items.Add(web.Author.ToString());
        }

Listing all lists in the website
SPSite site = new SPSite("http://localhost/SiteDirectory/IT"); //IT-site name
        SPWeb web = site.OpenWeb();
        SPList list = web.Lists["Posts"]; // a List in the site
        foreach(SPListItem col in list.Items)
        {
            DropDownList2.Items.Add(col.Title.ToString()); // Item in the List
        }