add Avalonia Dialogs

Pilz.UI.AvaloniaUI/Dialogs/AvaloniaDialogBase.axaml.cs

@@ -0,0 +1,27 @@
+using Avalonia.Controls;
+
+namespace Pilz.UI.AvaloniaUI.Dialogs;
+
+public partial class AvaloniaDialogBase : Window
+{
+    protected AvaloniaFlyoutBase? dialogPanel;
+
+    public AvaloniaFlyoutBase DialogPanel => dialogPanel ?? throw new NullReferenceException();
+
+    public AvaloniaDialogBase()
+    {
+        InitializeComponent();
+    }
+
+    public void SetContent(AvaloniaFlyoutBase content)
+    {
+        dialogPanel = content;
+        dialogPanel.OnClose += DialogPanelOnOnClose; 
+        Content = content;
+    }
+
+    private void DialogPanelOnOnClose(object? sender, EventArgs e)
+    {
+        Close(DialogPanel.Result);
+    }
+}