NumPad 修复了 官方NumericUpDown对NumPad不响应的问题

NumPad 修复了 当Target不是TextBox的时候，NumPad上的Delete和Back不响应的问题
IPv4Box 修复了 由于失去焦点所以对 NumPad 不响应的问题

src/Ursa/Controls/IPv4Box/IPv4Box.cs

@@ -107,7 +107,25 @@ public class IPv4Box: TemplatedControl
             e.Client = tb._imClient;
         });
     }
-    
+
+    /// <summary>
+    /// <20>Ƿ<EFBFBD>ʹ<EFBFBD><CAB9>С<EFBFBD><D0A1><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
+    /// </summary>
+    internal bool IsTargetByNumPad 
+    {
+        set
+        {
+            if(_isTargetByNumPad
+                &&!value)
+            {
+                SetLostFocus();
+            }
+            _isTargetByNumPad =value;
+        }
+        get => _isTargetByNumPad;
+    }
+    private bool _isTargetByNumPad;
+
     #region Overrides
     protected override void OnApplyTemplate(TemplateAppliedEventArgs e)
     {
@@ -308,6 +326,15 @@ public class IPv4Box: TemplatedControl
     protected override void OnLostFocus(RoutedEventArgs e)
     {
         base.OnLostFocus(e);
+        if (IsTargetByNumPad)
+        {
+            return;
+        }
+        SetLostFocus();
+    }
+
+    private void SetLostFocus()
+    {
         foreach (var pre in _presenters)
         {
             pre?.HideCaret();
@@ -317,7 +344,8 @@ public class IPv4Box: TemplatedControl
         ParseBytes(ShowLeadingZero);
         SetIPAddressInternal();
     }
-    
+
+
     protected override void OnGotFocus(GotFocusEventArgs e)
     {
         _currentActivePresenter = _firstText;