feat: add recall as internal function to overlay dialog.

demo/Ursa.Demo/Pages/BannerDemo.axaml

@@ -48,5 +48,8 @@
             </Border>
         </Grid>
         <TextBox u:NumPad.Attach="True" Width="100" Watermark="Invoke NumPad"></TextBox>
+        <TextBox u:NumPad.Attach="True" Width="100" Watermark="Invoke NumPad"></TextBox>
+        <TextBox u:NumPad.Attach="True" Width="100" Watermark="Invoke NumPad"></TextBox>
+        <u:NumericIntUpDown u:NumPad.Attach="True" Width="100" Watermark="Invoke NumPad"></u:NumericIntUpDown>
     </StackPanel>
 </UserControl>

src/Ursa/Controls/Dialog/OverlayDialog.cs

@@ -212,5 +212,11 @@ public static class OverlayDialog
         control.CanDragMove = options.CanDragMove;
     }
 
-    
+    internal static T? Recall<T>(string? hostId) where T: Control
+    {
+        var host = OverlayDialogManager.GetHost(hostId);
+        if (host is null) return null;
+        var item = host.Recall<T>();
+        return item;
+    }
 }

src/Ursa/Controls/NumPad/NumPad.cs

@@ -54,6 +54,13 @@ public class NumPad: TemplatedControl
     
     private static void OnTargetGotFocus(object sender, GotFocusEventArgs e)
     {
+        if (sender is not InputElement) return;
+        var existing = OverlayDialog.Recall<NumPad>(null);
+        if (existing is not null)
+        {
+            existing.Target = sender as InputElement;
+            return;
+        }
         var numPad = new NumPad() { Target = sender as InputElement };
         OverlayDialog.ShowCustom(numPad, new object());
     }

src/Ursa/Controls/NumericUpDown/NumericUpDownBase.cs

@@ -216,6 +216,11 @@ public abstract class NumericUpDown : TemplatedControl, IClearControl
         
     }
 
+    protected override void OnTextInput(TextInputEventArgs e)
+    {
+        _textBox?.RaiseEvent(e);
+    }
+
     private void OnDragPanelPointerReleased(object sender, PointerReleasedEventArgs e)
     {
         _point = null;

src/Ursa/Controls/OverlayShared/OverlayDialogHost.Shared.cs

@@ -189,4 +189,10 @@ public partial class OverlayDialogHost: Canvas
         }
         return result;
     }
+
+    internal T? Recall<T>()
+    {
+        var element = _layers.LastOrDefault(a => a.Element.Content?.GetType() == typeof(T));
+        return element?.Element.Content is T t ? t : default;
+    }
 }