completed the branch

src/Shared/HandyControlDemo_Shared/ViewModel/Controls/TagDemoViewModel.cs

@@ -1,13 +1,50 @@
-using HandyControlDemo.Data;
+using System;
+using System.Collections.ObjectModel;
+using GalaSoft.MvvmLight;
+using GalaSoft.MvvmLight.Command;
+using HandyControl.Controls;
+using HandyControlDemo.Data;
+using HandyControlDemo.Properties.Langs;
 using HandyControlDemo.Service;
 
 namespace HandyControlDemo.ViewModel
 {
-    public class TagDemoViewModel : DemoViewModelBase<DemoDataModel>
+    public class TagDemoViewModel : ViewModelBase
     {
         public TagDemoViewModel(DataService dataService)
         {
-            DataList = dataService.GetDemoDataList(10);
+            DataList = new ObservableCollection<DemoDataModel>(dataService.GetDemoDataList(10));
         }
+
+        public ObservableCollection<DemoDataModel> DataList { get; set; }
+
+        private string _tagName;
+
+        public string TagName
+        {
+            get => _tagName;
+#if NET40
+            set => Set(nameof(TagName), ref _tagName, value);
+#else
+            set => Set(ref _tagName, value);
+#endif
+        }
+
+        public RelayCommand AddItemCmd => new Lazy<RelayCommand>(() =>
+            new RelayCommand(() =>
+            {
+                if (string.IsNullOrEmpty(TagName))
+                {
+                    Growl.Warning(Lang.PlsEnterContent);
+                    return;
+                }
+
+                DataList.Insert(0, new DemoDataModel
+                {
+                    IsSelected = DataList.Count % 2 == 0,
+                    Name = TagName
+                });
+                TagName = string.Empty;
+            })).Value;
     }
 }

src/Shared/HandyControlDemo_Shared/ViewModel/ViewModelLocator.cs

@@ -98,7 +98,7 @@ namespace HandyControlDemo.ViewModel
 
         public SplitButtonDemoViewModel SplitButtonDemo => SimpleIoc.Default.GetInstance<SplitButtonDemoViewModel>();
 
-        public TagDemoViewModel TagDemo => SimpleIoc.Default.GetInstance<TagDemoViewModel>();
+        public TagDemoViewModel TagDemo => new TagDemoViewModel(SimpleIoc.Default.GetInstance<DataService>());
 
         #endregion
     }