1.项目下载地址：https://gitee.com/confusedkitten/avalonia-demo

2.UI库Semi.Avalonia，项目地址  https://github.com/irihitech/Semi.Avalonia

3.样式预览

4.PositionControl.axaml 

<UserControl xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
             x:Class="AvaloniaDemo.Pages.PositionControl">
	<Grid RowDefinitions="*,*" ColumnDefinitions="*,*">
		<Grid Background="Green" PointerPressed = "PointerPressed">
			
		</Grid>
		<Grid Grid.Row="1" Grid.Column="1" Background="Purple" PointerPressed = "PointerPressed">

		</Grid>
		<Grid Grid.Row="0" Grid.Column="1" Background="Pink" PointerPressed = "PointerPressed">

		</Grid>
		<Grid Grid.Row="1" Grid.Column="0" Background="Wheat" PointerPressed = "PointerPressed">

		</Grid>
	</Grid>
</UserControl>

5.PositionControl.axaml.cs

using Avalonia;
using Avalonia.Controls;
using Avalonia.Input;
using Avalonia.Markup.Xaml;
using System;

namespace AvaloniaDemo.Pages;

public partial class PositionControl : UserControl
{
    PositionWindow positionWindow = new PositionWindow();
    public PositionControl()
    {
        InitializeComponent();
        Grid grid = new Grid();
    }

    private void PointerPressed(object? sender, PointerPressedEventArgs e)
    {
        positionWindow = new PositionWindow();
        if (sender is Grid grid && this.VisualRoot is Window root)
        {
            if (grid.TranslatePoint(new Point(0, 0), root) is Point p)
            {
                var p1 = root.PointToScreen(p);
                positionWindow.Position = p1;
                positionWindow.ShowDialog(root);
            }
        }
    }
}