feat: add resources.

src/Ursa/Controls/Loading/LoadingContainer.cs

@@ -0,0 +1,59 @@
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Controls.Metadata;
+using Avalonia.Controls.Templates;
+
+namespace Ursa.Controls;
+
+[PseudoClasses(PC_Loading)]
+public class LoadingContainer: ContentControl
+{
+    public const string PC_Loading = ":loading";
+    
+    public static readonly StyledProperty<object?> IndicatorProperty = AvaloniaProperty.Register<LoadingContainer, object?>(
+        nameof(Indicator));
+
+    public object? Indicator
+    {
+        get => GetValue(IndicatorProperty);
+        set => SetValue(IndicatorProperty, value);
+    }
+
+    public static readonly StyledProperty<object?> LoadingMessageProperty = AvaloniaProperty.Register<LoadingContainer, object?>(
+        nameof(LoadingMessage));
+
+    public object? LoadingMessage
+    {
+        get => GetValue(LoadingMessageProperty);
+        set => SetValue(LoadingMessageProperty, value);
+    }
+
+    public static readonly StyledProperty<IDataTemplate> LoadingMessageTemplateProperty = AvaloniaProperty.Register<LoadingContainer, IDataTemplate>(
+        nameof(LoadingMessageTemplate));
+
+    public IDataTemplate LoadingMessageTemplate
+    {
+        get => GetValue(LoadingMessageTemplateProperty);
+        set => SetValue(LoadingMessageTemplateProperty, value);
+    }
+
+    public static readonly StyledProperty<bool> IsLoadingProperty = AvaloniaProperty.Register<LoadingContainer, bool>(
+        nameof(IsLoading));
+
+    public bool IsLoading
+    {
+        get => GetValue(IsLoadingProperty);
+        set => SetValue(IsLoadingProperty, value);
+    }
+
+    static LoadingContainer()
+    {
+        IsLoadingProperty.Changed.AddClassHandler<LoadingContainer>((x, e) => x.OnIsLoadingChanged(e));
+    }
+
+    private void OnIsLoadingChanged(AvaloniaPropertyChangedEventArgs args)
+    {
+        bool newValue = args.GetNewValue<bool>();
+        PseudoClasses.Set(PC_Loading, newValue);
+    }
+}