LevelHostControl.xaml

<local:LevelHostControl x:Name="levelHostControl" Height="580" Width="810" Canvas.Left="0" Canvas.Top="0" HostFile="Level1.xaml"/>

<UserControl
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    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"
    x:Class="BeeHive.LevelHostControl"
    d:DesignWidth="640" d:DesignHeight="480">

    <Grid x:Name="LayoutRoot">
        <ContentPresenter x:Name="PART_CONTENT"/>
    </Grid>
</UserControl>

using System;
using System.IO;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Markup;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Resources;
using System.Windows.Shapes;

namespace BeeHive
{
    public partial class LevelHostControl : UserControl
    {
        public static readonly DependencyProperty HostFileProperty = 
        DependencyProperty.Register("HostFile", 
                                    typeof(object), 
                                    typeof(LevelHostControl), 
                                    new PropertyMetadata(null, new PropertyChangedCallback(OnHostFileChanged)));
        
        public string HostFile
        {
            get { return (string)this.GetValue(HostFileProperty); }
            set { this.SetValue(HostFileProperty, value); }
        }

        private static void OnHostFileChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
        {
            LevelHostControl hostControl = (LevelHostControl)sender;
            string newValue = (string)e.NewValue;

            if (!string.IsNullOrEmpty(newValue))
            {
                Uri uri = new Uri("/BeeHive;component/" + newValue, UriKind.Relative);
                StreamResourceInfo streamResourceInfo = Application.GetResourceStream(uri);
                StreamReader sr = new StreamReader(streamResourceInfo.Stream);

                object loadedLevel = XamlReader.Load(sr.ReadToEnd());
                hostControl.PART_CONTENT.Content = loadedLevel;
            }
        }
        
        
        public LevelHostControl()
        {
            // 为初始化变量所必需
            InitializeComponent();
        }
    }
}