title: Datepicker double SelectedDateChanged event when typing date only
body: <p>I have some code which has an unexpected behavior depending on how you use the DatePicker control. If you use the DatePicker by selecting the date via the mouse the event is fired once and the code works correctly. Though if you type in the date the event is triggered twice.
  Here is my xaml code.</p>
  
  <pre><code>&lt;DatePicker Margin="0,-1,0,0" Height="23" VerticalAlignment="Top"    HorizontalAlignment="Right" Width="190" SelectedDate="{Binding DaDate}"&gt;
      &lt;i:Interaction.Triggers&gt;
          &lt;i:EventTrigger EventName="SelectedDateChanged"&gt;
              &lt;i:InvokeCommandAction Command="{Binding SelectedDaDateChangedCommand}" /&gt;
          &lt;/i:EventTrigger&gt;
      &lt;/i:Interaction.Triggers&gt;
  &lt;/DatePicker&gt;
  </code></pre>
  
  <p>And c# bits.</p>
  
  <pre><code>public ICommand SelectedDaDateChangedCommand { get; set; }
  private DateTime? daDate;
  public DateTime? DaDate
  {
      get { return daDate; }
      set
      {
          daDate = value;
          NotifyOfPropertyChange(() =&gt; DaDate);
      }
  }
  
  public MisoConstraintsViewModel(IView v) : base(v)
  {
      //This is where DoStuff() gets called twice from the SelectedDateChanged
      SelectedDaDateChangedCommand = new RelayCommand(p =&gt; DoStuff());
  }
  </code></pre>
  
  <p>Any help is appreciated. Thanks.</p>