title: WPF Combobox not updating in twoways
body: <p>I am binding a combobox with a varaible on my PLC so when i change the combobox the changed value transmitted to my PLC but when i change on my PLC the combobox wont change even if the field is changed</p>
  
  <p>I put a brakepoint on the field(the one i bind to SelectedItem) to check if it changes and it did but didn't affect the combobox </p>
  
  <p>Here is my ViewModel</p>
  
  <pre><code>    List&lt;string&gt; _temperatureList = new List&lt;string&gt; { "80 °C", "100 °C", "120 °C" };
  
      public List&lt;string&gt; TemperatureList
      {
          get { return _temperatureList; }
      }
  
      public  string Temperature
      {
  
          get
          { 
              return (TemperatureGS != 0) ?  string.Format("{0} °C", TemperatureGS) : "80 °C";
          }
          set
          {
              TemperatureGS = Convert.ToSByte(value.Replace(" °C", ""));
              OnPropertyChanged();
              WriteTemperature(TemperatureGS);
          }
      }
  
      private short _temperature ;
  
      public short TemperatureGS
      {
          get { return _temperature; }
          set { SetProperty(ref _temperature, value); }
      }
  
  
  
   public void OnNavigatedTo(NavigationContext navigationContext)
          {
  
              TemperatureGS = PLCread(0);
              OnPropertyChanged(Temperature);
  
          }
  </code></pre>
  
  <p>My Xaml code</p>
  
  <pre><code> &lt;ComboBox  SelectedItem="{Binding Temperature, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged }"  
  ItemsSource="{Binding TemperatureList }"  /&gt;
  </code></pre>