Merge pull request #182 from Soar360/main

为 Pagination 控件增加 CurrentPageChanged 事件

demo/Ursa.Demo/Pages/PaginationDemo.axaml

@@ -24,6 +24,8 @@
             PageSizeOptions="10, 20, 50, 100"
             ShowQuickJump="{Binding #quickJumperSelector.IsChecked}"
             ShowPageSizeSelector="{Binding #pageSizeSelector.IsChecked}"
+			Command="{Binding LoadPageCommand}"
+			CommandParameter="{Binding $self.CurrentPage}"
             TotalCount="600" />
     </StackPanel>
 </UserControl>

demo/Ursa.Demo/ViewModels/PaginationDemoViewModel.cs

@@ -1,11 +1,25 @@
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
+using System.Diagnostics;
+using System.Windows.Input;
 using Avalonia.Collections;
 using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
 
 namespace Ursa.Demo.ViewModels;
 
 public class PaginationDemoViewModel : ViewModelBase
 {
     public AvaloniaList<int> PageSizes { get; set; } = new() { 10, 20, 50, 100 };
+
+    public ICommand LoadPageCommand { get; }
+    public PaginationDemoViewModel()
+    {
+        this.LoadPageCommand = new RelayCommand<int?>(LoadPage);
+    }
+
+    private void LoadPage(int? pageIndex)
+    {
+        Debug.WriteLine($"Loading page {pageIndex}");
+    }
 }

src/Ursa/Controls/Pagination/Pagination.cs

@@ -7,6 +7,7 @@ using Avalonia.Input;
 using Avalonia.Interactivity;
 using Avalonia.Styling;
 using Irihi.Avalonia.Shared.Helpers;
+using System.Windows.Input;
 
 namespace Ursa.Controls;
 
@@ -40,6 +41,43 @@ public class Pagination: TemplatedControl
         set => SetValue(CurrentPageProperty, value);
     }
 
+    private void OnCurrentPageChanged(AvaloniaPropertyChangedEventArgs<int?> args)
+    {
+        int? oldValue = args.GetOldValue<int?>();
+        int? newValue = args.GetNewValue<int?>();
+        var e = new ValueChangedEventArgs<int>(CurrentPageChangedEvent, oldValue, newValue);
+        RaiseEvent(e);
+    }
+
+    public static readonly RoutedEvent<ValueChangedEventArgs<int>> CurrentPageChangedEvent =
+        RoutedEvent.Register<Pagination, ValueChangedEventArgs<int>>(nameof(CurrentPageChanged), RoutingStrategies.Bubble);
+
+    /// <summary>
+    /// Raised when the <see cref="CurrentPage"/> changes.
+    /// </summary>
+    public event EventHandler<ValueChangedEventArgs<int>>? CurrentPageChanged
+    {
+        add => AddHandler(CurrentPageChangedEvent, value);
+        remove => RemoveHandler(CurrentPageChangedEvent, value);
+    }
+
+    public static readonly StyledProperty<ICommand?> CommandProperty = AvaloniaProperty.Register<Pagination, ICommand?>(
+        nameof(Command));
+
+    public ICommand? Command
+    {
+        get => GetValue(CommandProperty);
+        set => SetValue(CommandProperty, value);
+    }
+
+    public static readonly StyledProperty<object?> CommandParameterProperty = AvaloniaProperty.Register<Pagination, object?>(nameof(CommandParameter));
+
+    public object? CommandParameter
+    {
+        get => this.GetValue(CommandParameterProperty);
+        set => this.SetValue(CommandParameterProperty, value);
+    }
+
     public static readonly StyledProperty<int> TotalCountProperty = AvaloniaProperty.Register<Pagination, int>(
         nameof(TotalCount));
 
@@ -119,6 +157,8 @@ public class Pagination: TemplatedControl
         PageSizeProperty.Changed.AddClassHandler<Pagination, int>((pagination, args) => pagination.OnPageSizeChanged(args));
         CurrentPageProperty.Changed.AddClassHandler<Pagination, int?>((pagination, args) =>
             pagination.UpdateButtonsByCurrentPage(args.NewValue.Value));
+        CurrentPageProperty.Changed.AddClassHandler<Pagination, int?>((pagination, args) =>
+            pagination.OnCurrentPageChanged(args));
         TotalCountProperty.Changed.AddClassHandler<Pagination, int>((pagination, args) =>
             pagination.UpdateButtonsByCurrentPage(pagination.CurrentPage));
     }
@@ -180,12 +220,14 @@ public class Pagination: TemplatedControl
         value = Clamp(value.Value, 1, PageCount);
         SetCurrentValue(CurrentPageProperty, value);
         _quickJumpInput?.SetCurrentValue(NumericIntUpDown.ValueProperty, null);
+        InvokeCommand();
     }
 
     private void OnButtonClick(object? sender, RoutedEventArgs e)
     {
         var diff = Equals(sender, _previousButton) ? -1 : 1;
         AddCurrentPage(diff);
+        InvokeCommand();
     }
 
     private void InitializePanelButtons()
@@ -218,13 +260,14 @@ public class Pagination: TemplatedControl
                 CurrentPage = pageButton.Page;
             }
         }
+        InvokeCommand();
     }
 
     private void AddCurrentPage(int pageChange)
     {
         int newValue = (CurrentPage ?? 0) + pageChange;
         newValue = Clamp(newValue, 1, PageCount);
-        ; SetCurrentValue(CurrentPageProperty, newValue);
+        SetCurrentValue(CurrentPageProperty, newValue);
     }
 
     private int Clamp(int value, int min, int max)
@@ -312,4 +355,11 @@ public class Pagination: TemplatedControl
         if (_previousButton != null) _previousButton.IsEnabled = (CurrentPage ?? int.MaxValue) > 1;
         if (_nextButton != null) _nextButton.IsEnabled = (CurrentPage ?? 0) < PageCount;
     }
+    private void InvokeCommand()
+    {
+        if (this.Command != null && this.Command.CanExecute(this.CommandParameter))
+        {
+            this.Command.Execute(this.CommandParameter);
+        }
+    }
 }