feat: add localization. add realtime derivation of period from hour in NeedConfirm mode.

demo/Ursa.Demo/Pages/TimePickerDemo.axaml

@@ -21,8 +21,9 @@
             Width="300"
             Classes="ClearButton"
             DisplayFormat="HH 时 mm 分 ss 秒"
-            PanelFormat="HH mm ss tt"
+            PanelFormat="tt HH mm ss"
             HorizontalAlignment="Left"
+            NeedConfirmation="True"
             InnerLeftContent="时刻"
             InnerRightContent="截止" />
     </StackPanel>

src/Ursa.Themes.Semi/Controls/TimePicker.axaml

@@ -199,7 +199,7 @@
                                                 Margin="8"
                                                 HorizontalAlignment="Right"
                                                 Command="{Binding $parent[u:TimePicker].Confirm}"
-                                                Content="Confirm" />
+                                                Content="{DynamicResource STRING_DATE_TIME_CONFIRM}" />
                                         </StackPanel>
                                         <ContentPresenter
                                             Name="PART_PopupHeader"

src/Ursa.Themes.Semi/Locale/en-us.axaml

@@ -15,4 +15,5 @@
     <x:String x:Key="STRING_THEME_TOGGLE_DARK">Dark</x:String>
     <x:String x:Key="STRING_THEME_TOGGLE_LIGHT">Light</x:String>
     <x:String x:Key="STRING_THEME_TOGGLE_SYSTEM">System</x:String>
+    <x:String x:Key="STRING_DATE_TIME_CONFIRM">Confirm</x:String>   
 </ResourceDictionary>

src/Ursa.Themes.Semi/Locale/zh-cn.axaml

@@ -15,4 +15,5 @@
     <x:String x:Key="STRING_THEME_TOGGLE_DARK">暗色</x:String>
     <x:String x:Key="STRING_THEME_TOGGLE_LIGHT">亮色</x:String>
     <x:String x:Key="STRING_THEME_TOGGLE_SYSTEM">跟随系统</x:String>
+    <x:String x:Key="STRING_DATE_TIME_CONFIRM">确认</x:String>   
 </ResourceDictionary>

src/Ursa/Controls/DateTimePicker/TimePickerPresenter.cs

@@ -220,6 +220,7 @@ public class TimePickerPresenter : TemplatedControl
     private void OnPanelSelectionChanged(object sender, System.EventArgs e)
     {
         if (_updateFromTimeChange) return;
+        if (!_use12Clock && sender == _ampmSelector) return;
         var time = NeedsConfirmation ? _timeHolder : Time ?? DateTime.Now.TimeOfDay;
         var hour = _hourSelector?.SelectedValue ?? time.Hours;
         var minute = _minuteSelector?.SelectedValue ?? time.Minutes;
@@ -232,6 +233,15 @@ public class TimePickerPresenter : TemplatedControl
                 1 when hour < 12 => hour + 12,
                 _ => hour
             };
+        else
+        {
+            ampm = hour switch
+            {
+                >= 12 => 1,
+                _ => 0
+            };
+            _ampmSelector.SelectedValue = ampm;
+        }
         var newTime = new TimeSpan(hour, minute, second);
         if (NeedsConfirmation)
             _timeHolder = newTime;