title: implement multiple conditions in where clause C#
body: <p><strong>situation</strong> : i have a event handler of a search textbox in MainPage.xaml.cs</p>
  
  <pre><code>    void src_textbox_TextChanged(object sender, TextChangedEventArgs e)
      {
          TextBox tb = sender as TextBox;
  
          listBoxTextItems.ItemsSource = App.ViewModel.Problems.Where(w =&gt; w.ProblemName.ToLower().Contains(tb.Text));
  
      }
  </code></pre>
  
  <p>listBoxTextItems : name of listbox control ,<br>
  Problems : name of collection instantiated in MainViewModelClass constructor ,                                       </p>
  
  <p>this code shows only those objects whose <code>ProblemName</code> property contains the letters typed in textbox .</p>
  
  <p><strong>Problem</strong> : what i want is that this code should also show those objects whose <code>ProblemDesc</code> property contains the letters typed in textbox .                                             </p>
  
  <p>i tried something like this :</p>
  
  <pre><code>            listBoxTextItems.ItemsSource = App.ViewModel.Problems.Where((w =&gt; w.ProblemName.ToLower().Contains(tb.Text))||(w =&gt; w.ProblemDesc.ToLower().Contains(tb.Text)));
  </code></pre>
  
  <p>but i get an error saying "operator <code>||</code> cannot be applied to operands of type <code>lambda expression</code> and <code>lambda expression</code>. can anyone suggest me correct code ?</p>