Find All Web Application Using SPFarm Services

Step 1: Create web application class to store details about web application like name, owner details.

public class WebApplication
{
    public string Name { get; set; }
    public string Value { get; set; }
    public List<NameValuePair> SiteCollections { get; set; }
    public string Owner { get; set; }
    public string Name_Owner
    {
        get
        {
            return string.Format("{0} ({1})", this.Name, this.Owner);
        }
    }

    public WebApplication()
    {
        this.Name = this.Value = string.Empty;
        this.SiteCollections = new List<NameValuePair>();
    }

    public WebApplication(string name)
        : this()
    {
        this.Name = this.Value = name;
    }
    public WebApplication(string name, string value)
        : this()
    {
        this.Name = name;
        this.Value = value;

    }
}

Step 2: C# code to find All Web Applications. 

public class SharePointInformation

   private List<WebApplication> _allWebApplications;

   public List<WebApplication> GetAllWebApplication
   {
       get
       {
           if (_allWebApplications == null)
           {
               List<WebApplication> apps = new List<WebApplication>();

               try
               {

                   SPServiceCollection services = SPFarm.Local.Services;
                   foreach (SPService service in services)
                   {
                       if (service is SPWebService)
                       {
                           SPWebService webservice = (SPWebService)service;
                           WebApplication webApps = new WebApplication();
                           foreach (SPWebApplication webapp in webservice.WebApplications)
                           {
                               foreach (SPAlternateUrl spWebAppAlternateURL in webapp.AlternateUrls)
                               {
                                   if (spWebAppAlternateURL.UrlZone == SPUrlZone.Default)
                                   {
                                       webApps = new WebApplication(webapp.Name, spWebAppAlternateURL.Uri.AbsoluteUri);
                                       foreach (string site in webapp.Sites.Names)
                                       {
                                           if (site == "")
                                           {
                                               webApps.SiteCollections.Add(new NameValuePair() { Name = "/", Value = "/" });
                                           }
                                           else
                                               webApps.SiteCollections.Add(new NameValuePair() { Name = site, Value = site });
                                       }

                                       apps.Add(webApps);
                                   }
                               }
                           }
                       }
                   }

                   this._allWebApplications = apps;
               }
               catch(Exception ex)
               {
                   MessageBox.Show(ex.Message);
               }
           }
           return this._allWebApplications;
       }


       set
       {
           this._allWebApplications = value;
       }
   }