viewmodel ins wpf gepackt, build failed

DaSaSo.Wpf/ViewModel/HomeViewModel.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace DaSaSo.Wpf.ViewModel
+{
+    public class HomeViewModel : BaseViewModel
+    {
+        public string Welcome { get => "Herzlich willkommen"; }
+    }
+}