viewmodel ins wpf gepackt, build failed

DaSaSo.Wpf/ViewModel/SewerPictureDocumentationViewModel.cs

@@ -0,0 +1,33 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Drawing;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace DaSaSo.Wpf.ViewModel
+{
+    public static class BitmapConversion
+    {
+      //BitmapSource
+    }
+    public class SewerPictureDocumentationViewModel : BaseViewModel
+    {
+        
+        public ObservableCollection<TabItem> Tabs { get; set; }
+
+        public SewerPictureDocumentationViewModel()
+        {
+            Tabs = new ObservableCollection<TabItem>();
+            Tabs.Add(new TabItem { Header = "One", Content = "One's content" });
+            Tabs.Add(new TabItem { Header = "Two", Content = "Two content" });
+        }
+    }
+
+    public sealed class TabItem
+    {
+        public string Header { get; set; }
+        public string Content { get; set; }
+    }
+}