Rebuild Index

IndexRebuild.cs

string dbName = QueryString.Current["database"];
                        string itemPath = QueryString.Current["itemPath"];

                        if (!string.IsNullOrWhiteSpace(dbName) && !string.IsNullOrWhiteSpace(itemPath))
                        {
                            Sitecore.Data.Database db = Sitecore.Configuration.Factory.GetDatabase(dbName);
                            if (db != null)
                            {
                                rootItem = db.GetItem(itemPath);
                                if (rootItem != null)
                                {
                                    //Sitecore.Search.Index index = Sitecore.Search.SearchManager.GetIndex("sitecore_master_index");
                                    var index = rootItem.GetIndex();
                                    if (index != null)
                                    {
                                        stringBuilder.Append("Database Name: " + db.Name);
                                        stringBuilder.Append("<br/>Item Path: " + rootItem.Paths.FullPath);
                                        stringBuilder.Append("<br/>Index Name: " + index.Name);
                                        stopWatch = new System.Diagnostics.Stopwatch();
                                        stopWatch.Start();

                                        index.Rebuild();

                                        if (stopWatch != null)
                                        {
                                            stopWatch.Stop();
                                            stringBuilder.Append("<br/>Indexing Done Successfully!!!" + "<br/>Time Taken: " + stopWatch.Elapsed);
                                        }
                                    }
                                    else
                                    {
                                        stringBuilder.Append("Index is null.");
                                    }
                                }
                                else
                                {
                                    stringBuilder.Append("Root Item is null.");
                                }
                            }
                            else
                            {
                                stringBuilder.Append("Database is null.");
                            }
                        }
                        else
                        {
                            stringBuilder.Append("Please enter database & itemPath querystrings value.");
                        }