title: Entry binded value is always 0
body: <p>I got my numeric <code>entry</code> binded to viewmodel's <code>SelectedAmount</code>. Nevertheless <code>value</code> is always <code>0</code>, even if i put some value on gui in <code>entry</code> it goes to <code>property</code> and i see <code>_selectedAmount</code> as 0.
  What could be wrong?</p>
  <p><strong>Xaml:</strong></p>
  <pre><code>&lt;Entry Placeholder=&quot;Amount&quot; Text=&quot;{Binding SelectedAmount, Mode=TwoWay}&quot; Keyboard=&quot;Numeric&quot; MaxLength=&quot;5&quot; /&gt;
  </code></pre>
  <p><strong>ViewModel binded property:</strong></p>
  <pre><code>private int _selectedAmount;
  public int SelectedAmount
  {
      get =&gt; _selectedAmount;
      set
      {
          if (_selectedAmount &lt;= 0)
             _pageService.DisplayAlert(&quot;Warning&quot;, &quot;Value has to be between 1 - 10000&quot;, &quot;ok&quot;, &quot;cancel&quot;);
          else
              SetValue(ref _selectedAmount, value);
          }
  }
  </code></pre>