Add new create wpf app article (#193)

dotnet-desktop-guide/net/wpf/get-started/snippets/create-app-visual-studio/vb/Final.xaml.vb

@@ -0,0 +1,9 @@
+Public Class Final
+    '<FinalCode>
+    Private Sub ButtonAddName_Click(sender As Object, e As RoutedEventArgs)
+        If Not String.IsNullOrWhiteSpace(txtName.Text) And Not lstNames.Items.Contains(txtName.Text) Then
+            lstNames.Items.Add(txtName.Text)
+        End If
+    End Sub
+    '</FinalCode>
+End Class