title: WPF TextBox lostFocus event trigger
body: <p>I am new to WPF,
  In my mainWindow I have multiple TextBox, so whenever a user enters different inputs in these textbox I want to implement those changes in the code behind, as soon as user leaves the focus of the textbox.</p>
  
  <p>For example, my textBox looks like this:</p>
  
  <pre><code>&lt;TextBox Name="SpiralAngleTextBox"
                Grid.Column="1" Grid.Row="4"
                Margin="5,5,5,5" SelectedText="0"/&gt;
  </code></pre>
  
  <p>I am not looking to do any kind of input validation. What I want is to trigger some calculations or call a function whenever the TextBox leaves focus after contents of TextBox is updated.</p>