feat: try to add ime client.

src/Ursa/Controls/IPv4Box/IPv4Box.cs

@@ -7,6 +7,7 @@ using Avalonia.Controls.Primitives;
 using Avalonia.Data;
 using Avalonia.Input;
 using Avalonia.Input.Platform;
+using Avalonia.Input.TextInput;
 using Avalonia.Interactivity;
 using Avalonia.Media;
 using Avalonia.Media.TextFormatting;
@@ -96,11 +97,15 @@ public class IPv4Box: TemplatedControl
         get => GetValue(InputModeProperty);
         set => SetValue(InputModeProperty, value);
     }
-
+    private readonly IPv4BoxInputMethodClient _imClient = new IPv4BoxInputMethodClient();
     static IPv4Box()
     {
         ShowLeadingZeroProperty.Changed.AddClassHandler<IPv4Box>((o, e) => o.OnFormatChange(e));
         IPAddressProperty.Changed.AddClassHandler<IPv4Box>((o, e) => o.OnIPChanged(e));
+        TextInputMethodClientRequestedEvent.AddClassHandler<IPv4Box>((tb, e) =>
+        {
+            e.Client = tb._imClient;
+        });
     }
     
     #region Overrides

src/Ursa/Controls/IPv4Box/IPv4BoxInputMethodClient.cs

@@ -0,0 +1,44 @@
+using Avalonia;
+using Avalonia.Controls.Presenters;
+using Avalonia.Input.TextInput;
+
+namespace Ursa.Controls;
+
+public class IPv4BoxInputMethodClient:TextInputMethodClient
+{
+    private TextPresenter? _presenter;
+    public override Visual TextViewVisual => _presenter;
+    public override bool SupportsPreedit => false;
+    public override bool SupportsSurroundingText => true;
+
+    public override string SurroundingText
+    {
+        get;
+    }
+    public override Rect CursorRectangle { get; }
+    public override TextSelection Selection { get; set; }
+    private IPv4Box? _parent;
+    public void SetPresenter(TextPresenter? presenter, IPv4Box? parent)
+    {
+        if (this._parent != null)
+            this._parent.PropertyChanged -= new EventHandler<AvaloniaPropertyChangedEventArgs>(this.OnParentPropertyChanged);
+        this._parent = parent;
+        if (this._parent != null)
+            this._parent.PropertyChanged += new EventHandler<AvaloniaPropertyChangedEventArgs>(this.OnParentPropertyChanged);
+        TextPresenter presenter1 = this._presenter;
+        if (presenter1 != null)
+        {
+            presenter1.CaretBoundsChanged -= (EventHandler) ((s, e) => this.RaiseCursorRectangleChanged());
+        }
+        this._presenter = presenter;
+        if (this._presenter != null)
+            this._presenter.CaretBoundsChanged += (EventHandler) ((s, e) => this.RaiseCursorRectangleChanged());
+        this.RaiseTextViewVisualChanged();
+        this.RaiseCursorRectangleChanged();
+    }
+    
+    private void OnParentPropertyChanged(object? sender, AvaloniaPropertyChangedEventArgs e)
+    {
+        this.RaiseSelectionChanged();
+    }
+}