workElement及其DataContext保存到图像文件不

workElement及其DataContext保存到图像文件不

本文介绍了将FrameworkElement及其DataContext保存到图像文件不会成功的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

我有一个名为UserControl1的简单UserControl,其中包含一个TextBlock:

I have a simple UserControl called UserControl1 that contains a TextBlock:

  <UserControl x:Class="WpfApplication2.UserControl1"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
         mc:Ignorable="d"
         d:DesignHeight="300" d:DesignWidth="300">
     <Grid>
         <TextBlock Text="{Binding}"/>
     </Grid>
</UserControl>

我初始化了它的新实例,并在代码中为其提供了DataContext。当窗口关闭时,我必须将此控件绘制到图像文件。
UserControl不会在已创建的文件中渲染边界文本。

I initialized a new instance of it and gave it a DataContext in code. when the window is closing I have to draw this control to an image file.The UserControl does not render the bounded text in the file that been created.

这是我使用用户控件的代码:

and this is my code using the usercontrol:

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();

        Closing += MainWindow_Closing;
    }

    void MainWindow_Closing(object sender, CancelEventArgs e)
    {
        UserControl1 uc = new UserControl1();
        uc.DataContext = "hello";
        uc.Height = 100;
        uc.Width = 100;
        uc.Background = Brushes.LightBlue;
        DrawToImage(uc);
    }

    private void DrawToImage(FrameworkElement element)
    {
        element.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
        element.Arrange(new Rect(element.DesiredSize));

        RenderTargetBitmap bitmap = new RenderTargetBitmap((int)element.Width, (int)element.Height,
                                                           120.0, 120.0, PixelFormats.Pbgra32);
        bitmap.Render(element);

        BitmapEncoder encoder = new PngBitmapEncoder();
        encoder.Frames.Add(BitmapFrame.Create(bitmap));

        using (Stream s = File.OpenWrite(@"C:\555.png"))
        {
            encoder.Save(s);
        }
    }
}

我希望这很清楚,任何帮助将不胜感激。

I Hope It's clear enough, any help will be very appreciated.

推荐答案

您只是忘了在手动测量/排列后,在控件上强制进行Layout更新(

You just forgot to force a Layout update on your control after manually Measuring/Arrangeing it (which will not be enough to force binding resolving).

对使其起作用:

private void DrawToImage(FrameworkElement element)
{
    element.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
    element.Arrange(new Rect(element.DesiredSize));
    element.UpdateLayout();

    RenderTargetBitmap bitmap = new RenderTargetBitmap((int)element.Width, (int)element.Height,
                                                        120.0, 120.0, PixelFormats.Pbgra32);
    bitmap.Render(element);

    BitmapEncoder encoder = new PngBitmapEncoder();
    encoder.Frames.Add(BitmapFrame.Create(bitmap));

    using (Stream s = File.OpenWrite(@"C:\555.png"))
    {
        encoder.Save(s);
    }
}

编辑:有关绑定何时解决的更多信息:

Edit : More on when bindings are resolved : link

这篇关于将FrameworkElement及其DataContext保存到图像文件不会成功的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!

08-06 00:27