在 VB WPF 中未调用鼠标事件，z 顺序重要吗? [英] Mouse events not called in VB WPF, does z-order matter?

问题描述

google里有很多解释，但是我还是在努力实现鼠标事件.

There are many explanation in google, but I still struggling to implement mouse events.

• 我尝试在画布属性中使用 MouseEnter="Canvas1_MouseEnter"，但它不起作用.
• 我尝试手动添加，.它不起作用.
• 我也尝试在 Private Sub main_Loaded(sender As Object, e As RoutedEventArgs) Handles main.Loaded 方法中使用 AddHandler Canvas1.MouseEnter, AddressOf Canvas1_MouseEnter 方法，它没有也不行.
• 然后我尝试将 AddHandler Canvas1.MouseEnter, AddressOf Canvas1_MouseEnter 移动到 MainWindow.g.i.vb 文件中的 Public Sub InitializeComponent().它没有用

• I have tried to use MouseEnter="Canvas1_MouseEnter" in canvas properties, but it doesn't work.
• I tried to add manually, . it doesn't work.
• I also tried to use AddHandler Canvas1.MouseEnter, AddressOf Canvas1_MouseEnter in Private Sub main_Loaded(sender As Object, e As RoutedEventArgs) Handles main.Loaded method, it doesn't work too.
• Then I tried to move AddHandler Canvas1.MouseEnter, AddressOf Canvas1_MouseEnterto Public Sub InitializeComponent() in MainWindow.g.i.vb file. it didn't work

我不知道如何实现鼠标事件.:(

I have no idea how to implement mouse events. :(

所以我尝试将 MouseEnter 实现到它自己的表单中，正确调用事件.

so I tried to implement MouseEnter to the form it self, the event called properly.

这是否意味着 z 顺序很重要?

Does it mean z-order matter?

这里是xaml文件

<Window x:Name="main" x:Class="MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="620.242" Width="827.423">
    <Grid HorizontalAlignment="Left" Height="575" Margin="10,10,0,0" VerticalAlignment="Top" Width="807">
        <Canvas x:Name="Canvas1" HorizontalAlignment="Left" Height="555" Margin="794,368,-774,-348" VerticalAlignment="Top" Width="787" />
    </Grid>

</Window>

和处理程序子

    'this code generated automatically
     Private Sub Canvas1_MouseEnter(sender As Object, e As MouseEventArgs)
        MessageBox.Show("event called")
    End Sub 

如何在画布上实现鼠标事件?任何帮助表示赞赏:)

How could I implement mouse event to my canvas? Any help appreciated :)

推荐答案

WPF 中的 UI 元素不会在其呈现区域之外接收鼠标事件(没有鼠标捕获).除非您为其 Background 属性定义非空值，否则面板(如您的画布)不会呈现其子元素区域之外的任何内容.

UI elements in WPF do not receive mouse events (without mouse capture) outside their rendered area. A Panel (like your Canvas) does not render anything outside the area of its child elements unless you define a non-null value for its Background property.

你可以为你的 Canvas 设置一个 Background 如下所示，这使得它使用透明画笔渲染由 ActualWidth 和 ActualHeight 定义的整个区域:

You may set a Background for your Canvas like shown below, which makes it render the entire area defined by its ActualWidth and ActualHeight with a transparent brush:

<Canvas x:Name="Canvas1" Background="Transparent"
        MouseEnter="Canvas1_MouseEnter" ... />

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