title: Tcl/Tk: how to trigger bind function inside script instead of GUI operation
body: <p>In my Tcl/Tk script, there is combobox widget, and I bind an event to it, if the user change the selection of  the combobox, the bind function will be triggered. <br>
  Now I want to trigger the bind function inside script, instead of from GUI operation, how to do this? the code goes as following:</p>
  
  <pre><code>ttk::combobox .combo_select_tag -background white;
  .combo_select_tag configure -value "1 2 3";
  pack .combo_select_tag
  
  bind .combo_select_tag &lt;&lt;ComboboxSelected&gt;&gt; {
      puts "trigger\n"
  }
  </code></pre>