chore: update textbox demo.

src/Shared/HandyControlDemo_Shared/ViewModel/Common/InputElementDemoViewModel.cs

@@ -13,6 +13,8 @@ public class InputElementDemoViewModel : ViewModelBase
 {
     private string _email1;
     private string _email2;
+    private string _text1;
+    private string _text2;
     private double _doubleValue1;
     private double _doubleValue2;
     private IList<string> _dataList;
@@ -38,6 +40,26 @@ public class InputElementDemoViewModel : ViewModelBase
 #endif
     }
 
+    public string Text1
+    {
+        get => _text1;
+#if NET40
+        set => Set(nameof(Text1), ref _text1, value);
+#else
+        set => Set(ref _text1, value);
+#endif
+    }
+
+    public string Text2
+    {
+        get => _text2;
+#if NET40
+        set => Set(nameof(Text2), ref _text2, value);
+#else
+        set => Set(ref _text2, value);
+#endif
+    }
+
     public double DoubleValue1
     {
         get => _doubleValue1;