title: Xamarin forms set Picker SelectedItem
body: <p>I am working with a xamarin Forms.
  I am using <code>Picker</code> for DropDownList.</p>
  
  <p>How can I set selectedItem to Picker?</p>
  
  <p>My code</p>
  
  <pre><code>&lt;Picker x:Name="VendorName" Title="Select" ItemDisplayBinding="{Binding VendorName}" SelectedItem="{Binding VendorName}" Style="{StaticResource PickerStyle}"&gt;&lt;/Picker&gt;
  </code></pre>
  
  <p>and server side code is</p>
  
  <pre><code>Device.BeginInvokeOnMainThread(() =&gt;
  {
  VendorName.ItemsSource = VendorList;
  });
  
  var currentVendor = new List&lt;Vendor&gt;();
  currentVendor.Add(new Vendor { VendorID = "111", VendorName = "aaaa" });
  
  VendorName.SelectedItem = currentVendor;
  </code></pre>