win8.1 如何实现把一个page变成图片

Question

大概需求是这样，点击grdview里的某一个数据项，打开详细页，假如详细页里有一些控件或图形，如何把这个打开的详细页变成一个缩略图（或者图片）显示到 当前点击gridview数据项上面？不知道大家有没有听明白啊

Answer 1

你好，

可以使用RenderTargetBitmap（8.1的新内容）来实现对控件的截图，不过你需要后台先实例化这个页面，然后对Page控件截图，操作起来可能比较麻烦。

--James

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Answer 2

追问一下，当我调用  await renderTargetBitmap.RenderAsync(view);这个方法时候，报了一个错误，“Value does not fall within the expected range.”这是怎么回事，是不是对view的值有要求，我手动改了view的高度和宽度也不行，我这里的view是一个Grid

Answer 3

你好 lxdhuainan,

应该不是高度和宽度的问题，而是RenderTargetBitmap这个方法只能对可视的UIElement进行截图，我这里有一个解决方案。

你需要在Page中添加一个Frame，名字叫ScenarioOutput，同时有一个Image用来陈放对应的截图：

        private async void Button_Click(object sender, RoutedEventArgs e)
        {
            ScenarioOutput.Navigate(typeof(BasicPage1));
            RenderTargetBitmap renderTargetBitmap = new RenderTargetBitmap();
            await renderTargetBitmap.RenderAsync(ScenarioOutput);
            RenderedImage.Source = renderTargetBitmap;
            ScenarioOutput.Visibility = Windows.UI.Xaml.Visibility.Collapsed;
        }

对应的截图如下，蓝框为我们截图的结果，你可能需要自己改一下参数什么的。

--James

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Answer 4

感谢您的回答，经测试发现，如果是后台编码生成一系列控件，然后把控件对象传给

RenderTargetBitmap ，这样好像不行，必须是把控件放到xaml页面上才可以  这样问题就大了，我那个page是空的，里面就放了一个grid，然后后台动态给grid添加子项来渲染页面

Answer 5

那这样的话，除非你在Frame里加载page的时候也一并把grid加载了，要不然应该没法做实时截图。

或者你是否考虑过使用静态图片来代替，因为GirdView的数据项的尺寸也不大。

--James

---

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