修复 IPv4Box PinCode TimeBox 对 Delete 键的支持

#https://github.com/irihitech/Ursa.Avalonia/issues/590

src/Ursa/Controls/IPv4Box/IPv4Box.cs

@@ -214,7 +214,13 @@ public class IPv4Box: TemplatedControl
 
         if (e.Key == Key.Back)
         {
-            DeleteImplementation(_currentActivePresenter);
+            DeleteImplementation(_currentActivePresenter, isDeleteKey: false);
+            e.Handled = true;
+            return;
+        }
+        if (e.Key == Key.Delete)
+        {
+            DeleteImplementation(_currentActivePresenter, isDeleteKey: true);
             e.Handled = true;
             return;
         }
@@ -474,7 +480,11 @@ public class IPv4Box: TemplatedControl
         }
     }
 
-    private void DeleteImplementation(TextPresenter? presenter)
+    /// <summary>
+    /// </summary>
+    /// <param name="presenter"></param>
+    /// <param name="isDeleteKey">del 键 (从前往后删)</param>
+    private void DeleteImplementation(TextPresenter? presenter, bool isDeleteKey)
     {
         if (presenter is null) return;
         var oldText = presenter.Text ?? string.Empty;
@@ -483,7 +493,40 @@ public class IPv4Box: TemplatedControl
             presenter.DeleteSelection();
             presenter.ClearSelection();
         }
-        else if (string.IsNullOrWhiteSpace(oldText) || presenter.CaretIndex == 0)
+        else if (isDeleteKey)
+        {
+            if (string.IsNullOrWhiteSpace(oldText) || presenter.CaretIndex == oldText.Length)
+            {
+                presenter.HideCaret();
+                var oldActivePresenter = _currentActivePresenter;
+                MoveToNextPresenter(presenter, selectAllAfterMove: false);
+                if (_currentActivePresenter != null)
+                {
+                    _currentActivePresenter.ShowCaret();
+                    if (!ReferenceEquals(oldActivePresenter, _currentActivePresenter))
+                    {
+                        _currentActivePresenter.MoveCaretToStart();
+                    }
+                }
+            }
+            else
+            {
+                var index = presenter.CaretIndex;
+                var newText = string.Empty;
+                if (index == 0)
+                {
+                    newText = oldText.Substring(1, oldText.Length - 1);
+                }
+                else
+                {
+                    newText = oldText.Substring(0, index) + oldText.Substring(index + 1);
+                }
+                presenter.Text = newText;
+            }
+        }
+        else
+        {
+            if (string.IsNullOrWhiteSpace(oldText) || presenter.CaretIndex == 0)
             {
                 presenter.HideCaret();
                 MoveToPreviousTextPresenter(presenter);
@@ -501,6 +544,7 @@ public class IPv4Box: TemplatedControl
                 presenter.Text = newText;
             }
         }
+    }
 
     private void OnPressRightKey()
     {

src/Ursa/Controls/PinCode/PinCode.cs

@@ -209,6 +209,17 @@ public class PinCode : TemplatedControl
             _currentIndex--;
             _itemsControl?.ContainerFromIndex(_currentIndex)?.Focus();
         }
+        else if (e.Key == Key.Delete && _currentIndex < Digits.Count)
+        {
+            _currentIndex = MathHelpers.SafeClamp(_currentIndex, 0, Count - 1);
+            var presenter = _itemsControl?.ContainerFromIndex(_currentIndex) as PinCodeItem;
+            if (presenter is null) return;
+            Digits[_currentIndex] = string.Empty;
+            presenter.Text = string.Empty;
+            if (_currentIndex == Digits.Count-1) return;
+            _currentIndex++;
+            _itemsControl?.ContainerFromIndex(_currentIndex)?.Focus();
+        }
         else if (e.Key is Key.Left or Key.FnLeftArrow)
         {
             _currentIndex--;

src/Ursa/Controls/TimeBox.cs

@@ -251,7 +251,11 @@ public class TimeBox : TemplatedControl
         }
         else if (e.Key == Key.Back)
         {
-            DeleteImplementation(_currentActiveSectionIndex.Value);
+            DeleteImplementation(_currentActiveSectionIndex.Value, isDeleteKey: false);
+        }
+        else if (e.Key == Key.Delete)
+        {
+            DeleteImplementation(_currentActiveSectionIndex.Value, isDeleteKey: true);
         }
         else if (e.Key == Key.Right)
         {
@@ -596,7 +600,11 @@ public class TimeBox : TemplatedControl
         }
     }
 
-    private void DeleteImplementation(int index)
+    /// <summary>
+    /// </summary>
+    /// <param name="index"></param>
+    /// <param name="isDeleteKey">del 键 (从前往后删)</param>
+    private void DeleteImplementation(int index, bool isDeleteKey)
     {
         if (index < 0 || index > 3) return;
         var oldText = _presenters[index].Text??string.Empty;
@@ -605,7 +613,30 @@ public class TimeBox : TemplatedControl
             _presenters[index].DeleteSelection();
             _presenters[index].ClearSelection();
         }
-        else if (string.IsNullOrWhiteSpace(oldText) || _presenters[index].CaretIndex == 0)
+        else if (isDeleteKey)
+        {
+            if (string.IsNullOrWhiteSpace(oldText) || _presenters[index].CaretIndex == oldText.Length)
+            {
+                MoveToNextSection(index);
+            }
+            else
+            {
+                int caretIndex = _presenters[index].CaretIndex;
+                var newText = string.Empty;
+                if (caretIndex == 0)
+                {
+                    newText = oldText.Substring(1, oldText.Length - 1);
+                }
+                else
+                {
+                    newText = oldText.Substring(0, caretIndex) + oldText.Substring(caretIndex + 1);
+                }
+                _presenters[index].Text = newText;
+            }
+        }
+        else
+        {
+            if (string.IsNullOrWhiteSpace(oldText) || _presenters[index].CaretIndex == 0)
             {
                 MoveToPreviousSection(index);
             }
@@ -618,6 +649,7 @@ public class TimeBox : TemplatedControl
                 _presenters[index].Text = newText;
             }
         }
+    }
 
     private bool HandlingCarry(int index, int lowerCarry = 0)
     {