用MVVM模式开发中遇到的零散问题总结（5）——将动态加载的可视

<Grid >
        <Image Source="pack://siteoforigin:,/view/Print/Images/XXX.jpg" />
        <TextBlock Height="88" HorizontalAlignment="Left" Margin="928,1624,0" Text="{Binding Name}" VerticalAlignment="Top" Width="240" FontSize="64" />
    </Grid>

/// <summary>
        /// 设置需要生成的Xaml的地址
        /// </summary>
        public string XamlUrl
        {
            get { return (string)GetValue(XamlUrlProperty); }
            set { SetValue(XamlUrlProperty,value); }
        }
        public static readonly DependencyProperty XamlUrlProperty =
            DependencyProperty.Register("XamlUrl",typeof(string),typeof(CopXaml2Bmp),null);


        /// <summary>
        /// 生成的图片地址
        /// </summary>
        public string BmpUrl
        {
            get { return (string)GetValue(BmpUrlProperty); }
            set { SetValue(BmpUrlProperty,value); }
        }
        public static readonly DependencyProperty BmpUrlProperty =
            DependencyProperty.Register("BmpUrl",null);
        
        /// <summary>
        /// 设置dpi
        /// </summary>
        public int Dpi
        {
            get { return (int)GetValue(DpiProperty); }
            set { SetValue(DpiProperty,value); }
        }
        public static readonly DependencyProperty DpiProperty =
            DependencyProperty.Register("Dpi",typeof(int),null);

        

        private void UserControl_Loaded(object sender,RoutedEventArgs e)
        {
            try
            {       
                FileStream fs = new FileStream(XamlUrl,FileMode.Open,FileAccess.Read);//动态加载XAML                
                ContentControl myGrid = XamlReader.Load(fs) as ContentControl;
                //myGrid.DataContext = this.DataContext;//设置datacontext
                double width = (this.Parent as Grid).Width;//获取母容器的高宽
                double height = (this.Parent as Grid).Height;

                myGrid.Loaded += new RoutedEventHandler((sender1,e1) =>
                {
                    (this.Parent as Grid).Children.Remove(myGrid);//从母容器中移除该内容

                    var size = new Size(myGrid.Width,myGrid.Height);
                    myGrid.Measure(size);//二次布局,因为只是在内存中没有显示在UI上，需要经过布局才有内容
                    myGrid.Arrange(new Rect(new Point(0,0),size));

                    System.IO.FileStream fs1 = new System.IO.FileStream(BmpUrl,System.IO.FileMode.Create);//创建一个文件流来存图片
                    RenderTargetBitmap bmp = new RenderTargetBitmap((int)myGrid.Width,(int)myGrid.Height,Dpi,PixelFormats.Default);//visual对象转位图
                    bmp.Render(myGrid);//呈现visual
                    BitmapEncoder encoder = new TiffBitmapEncoder();//编码为图像流
                    encoder.Frames.Add(BitmapFrame.Create(bmp));//添加帧
                    encoder.Save(fs1);//保存文件
                    fs1.Close();

                    (this.Parent as Grid).Width = width;//大小还原
                    (this.Parent as Grid).Height = height;
                });
                (this.Parent as Grid).Width = myGrid.Width;//将母容器的高宽设置为需要的大小
                (this.Parent as Grid).Height = myGrid.Height;
                (this.Parent as Grid).Children.Add(myGrid);//添加进母容器让其暂时显示，以显示绑定的信息

                
            }
            catch
            {

            }
        }

<Assistant:Xaml2Bmp XamlUrl="view/Print/XXX.xaml" BmpUrl="d:/test.bmp" Dpi="96" HorizontalAlignment="Right" Height="100" Margin="0,204,44" VerticalAlignment="Bottom" Width="100"/>