Why my PropertyGrid is empty

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Model class:

using System;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;

namespace AvaloniaApp1.Models;

public class ProductItem
{
    [Key]
    [Browsable(false)]
    public Guid Id { get; set; }

    [DisplayName("产品名称")]
    [MinLength(1, ErrorMessage = "请输入此字段")]
    [RegularExpression(@"^\S(.*)", ErrorMessage = "请输入此字段")]
    public string Name { get; set; } = string.Empty;

    [DisplayName("产品型号")]
    public string ProductType { get; set; } = string.Empty;
}

.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"
             xmlns:vm="clr-namespace:AvaloniaApp1.ViewModels"
             xmlns:pgc="clr-namespace:Avalonia.PropertyGrid.Controls;assembly=Avalonia.PropertyGrid"
             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
             x:Class="AvaloniaApp1.Views.MainView"
             x:DataType="vm:MainViewModel">
	<Design.DataContext>
		<vm:MainViewModel />
	</Design.DataContext>
	
	<Grid>
		<pgc:PropertyGrid DataContext="ProductItemObj"/>
	</Grid>

</UserControl>

Am I missing something?

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After compiling, the effect is as follows:

[tsctsc6]

Oh, I should write {Binding ProductItemObj}. Problem solved.