How to get all SharePoint Web Applications in the Central Administration Page from code behind

Question

How can I have the list of all existing SharePoint Web Applications and their site collections from code behind .

Answer 1

foreach (SPWebApplication webApp in SPWebService.ContentService.WebApplications)
{
    string webUrl = webApp.GetResponseUri(SPUrlZone.Default).AbsoluteUri;
    SPSiteCollection sites = webApp.Sites;
}

Answer 2

SPWebApplicationCollection webAppColl = SPWebService.ContentService.WebApplications;

if (webAppColl != null)
 { 
   foreach (SPWebApplication spWebApp in webAppColl)
   {
        SPSiteCollection sites = spWebApp.Sites;
   }
}