private void SearchTextChanged() { Predicate <ThreadViewModel> filter = (ThreadViewModel tvm) => { if (tvm.InitialPost == null) { return(false); } return(tvm.InitialPost.SimpleComment.IndexOf(SearchText, StringComparison.OrdinalIgnoreCase) >= 0 || (tvm.InitialPost.Subject != null && tvm.InitialPost.Subject.IndexOf(SearchText, StringComparison.OrdinalIgnoreCase) >= 0)); }; Threads.ApplyFilter(filter); ImageThreads.ApplyFilter(filter); Watchlist.ApplyFilter(filter); }