Window.Loaded和Window.ContentRendered事件有什么区别？

问题描述

在WPF中的 Window.Loaded 和 Window.ContentRendered 事件之间有什么区别？是否首先发送了 ContentRendered 事件？

Window.ContentRendered 事件的描述只是说

Window.Loaded 事件的描述说

我有一个案例要将窗口的 MaxHeight 设置为正在显示我的窗口的屏幕的工作区域的高度。我应该怎么做？

编辑：

我想我找到了我正在寻找的东西，但我现在更困惑了加载的事件首先发生，然后发生 ContentRendered 事件。在Chris Sells& amp; Ian Griffiths说，加载事件是

虽然ContentRendered事件是

这与MSDN文档中关于加载事件：

现在更令人困惑。

解决方案

我认为这两个事件之间没有差别。为了理解这一点，我创建了一个简单的例子来操纵：

XAML

 < Window x：Class =LoadedAndContentRendered.MainWindow
 xmlns =http://schemas.microsoft.com/winfx/2006/xaml/ 
 xmlns：x =http://schemas.microsoft.com/winfx/2006/xaml
 Name =MyWindow
 Title =MainWindowHeight =1000 width =525
 WindowStartupLocation =CenterScreen
 ContentRendered =Window_ContentRendered
 Loaded =Window_Loaded> 
 
< Grid Name =RootGrid> 
< / Grid> 
< / Window> 
  

后面的代码

  private void Window_ContentRendered（object sender，EventArgs e）
 {
 MessageBox.Show（ContentRendered）; 
} 
 
 private void Window_Loaded（object sender，RoutedEventArgs e）
 {
 MessageBox.Show（Loaded）; 
} 
  

在这种情况下，消息加载出现在消息 ContentRendered 之后的第一个。这个确认文档中的信息。

一般来说，在WPF中，如果元素为： Loaded / p>

由于在WPF中， Window 是相同的元素，但它通常应该是在根面板中排列的内容（例如：网格）。因此，要监视 Window 的内容，并创建一个 ContentRendered 事件。来自MSDN的备注：

The description of the Window.Loaded event here says

I have a case where I want to set the window's MaxHeight to the height of the working area of the screen that is displaying my window. Which event should I do it in?

Edit:

I think I found what I was looking for, but I'm even more confused now. The Loaded event happens first and then the ContentRendered event happens. In the book Programming WPF by Chris Sells & Ian Griffiths, it says that the Loaded event is

While the 'ContentRendered` event is

This contradicts what the MSDN documentation says about the Loaded event:

This is even more confusing now.

解决方案

I think there is little difference between the two events. To understand this, I created a simple example to manipulation:

XAML

<Window x:Class="LoadedAndContentRendered.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Name="MyWindow"
        Title="MainWindow" Height="1000" Width="525"
        WindowStartupLocation="CenterScreen"
        ContentRendered="Window_ContentRendered"
        Loaded="Window_Loaded">

    <Grid Name="RootGrid">
    </Grid>
</Window>

Code behind

private void Window_ContentRendered(object sender, EventArgs e)
{
    MessageBox.Show("ContentRendered");
}

private void Window_Loaded(object sender, RoutedEventArgs e)
{
    MessageBox.Show("Loaded");
}

In this case the message Loaded appears the first after the message ContentRendered. This confirms the information in the documentation.

In general, in WPF the Loaded event fires if the element:

Since in WPF the Window is the same element, but it should be generally content that is arranged in a root panel (for example: Grid). Therefore, to monitor the content of the Window and created an ContentRendered event. Remarks from MSDN:

That is, if we create a Window:

<Window x:Class="LoadedAndContentRendered.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Name="MyWindow"
    ContentRendered="Window_ContentRendered"
    Loaded="Window_Loaded" />

It will only works Loaded event.

With regard to access to the elements in the Window, they work the same way. Let's create a Label in the main Grid of Window. In both cases we have successfully received access to Width:

private void Window_ContentRendered(object sender, EventArgs e)
{
    MessageBox.Show("ContentRendered: " + SampleLabel.Width.ToString());
}

private void Window_Loaded(object sender, RoutedEventArgs e)
{
    MessageBox.Show("Loaded: " + SampleLabel.Width.ToString());
}

As for the Styles and Templates, at this stage they are successfully applied, and in these events we will be able to access them.

For example, we want to add a Button:

private void Window_ContentRendered(object sender, EventArgs e)
{
    MessageBox.Show("ContentRendered: " + SampleLabel.Width.ToString());

    Button b1 = new Button();
    b1.Content = "ContentRendered Button";
    RootGrid.Children.Add(b1);
    b1.Height = 25;
    b1.Width = 200;
    b1.HorizontalAlignment = HorizontalAlignment.Right;
}

private void Window_Loaded(object sender, RoutedEventArgs e)
{
    MessageBox.Show("Loaded: " + SampleLabel.Width.ToString());

    Button b1 = new Button();
    b1.Content = "Loaded Button";
    RootGrid.Children.Add(b1);
    b1.Height = 25;
    b1.Width = 200;
    b1.HorizontalAlignment = HorizontalAlignment.Left;
}

In the case of Loaded event, Button to add to Grid immediately at the appearance of the Window. In the case of ContentRendered event, Button to add to Grid after all its content will appear.

Therefore, if you want to add items or changes before load Window you must use the Loaded event. If you want to do the operations associated with the content of Window such as taking screenshots you will need to use an event ContentRendered.

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