Add TimeBox Control

demo/Ursa.Demo/ViewModels/TimeBoxDemoViewModel.cs

@@ -0,0 +1,22 @@
+using System;
+using System.Net;
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+
+namespace Ursa.Demo.ViewModels;
+
+public partial class TimeBoxDemoViewModel : ObservableObject
+{
+    [ObservableProperty] private TimeSpan? _timeSpan;
+
+    [RelayCommand]
+    private void ChangeRandomTime()
+    {
+        TimeSpan = new TimeSpan(Random.Shared.NextInt64(0x00000000FFFFFFFF));
+    }
+    
+    public TimeBoxDemoViewModel()
+    {
+        TimeSpan = new TimeSpan(0, 21, 11, 36, 54);
+    }
+}