title: Vs2015 C# wpf can not reference control name after add a new control
body: <p>I am writing WPF using C# in VS2015.When I dragged a control, for example a textbox, to the disign view,and double click the textbox to create a event handle function,after that I try to reference this textbox by its name "textBox",but it said "the name 'textBox' does not exist in the current context".I can't fix this error unless I close the solution and reopen it(yes,when I reopen the solution,it can correctly reference the control).</p>
  
  <p>And I have a try to reset environment settings,it doesn't help.</p>