在用户控件中获取工具提示以显示数据绑定文本并保持打开状态

问题描述

我有一个用户控件，显示一个 TextBox 以及一个小的帮助图标。

I have a user control that shows a TextBox along with a small help icon.

我的目标是要有一个 ToolTip 弹出窗口，显示一些数据绑定文本，当鼠标悬停在帮助图标上时，保持打开状态。

My goal is to have a ToolTip pop-up, show some databound text and stay open when the mouse hovers over the help icon.

所以，为此，我在用户控件中创建了一个HelpText依赖属性，允许我将帮助文本字符串绑定到用户控件。

So, to that end I have created a HelpText dependency property in the user control allowing me to bind a help text string to the user control.

所以，我的用户控件看起来像这样

So, my user control looks something like this

<UserControl Name="textField" ...>
    <StackPanel Orientation="Horizontal">
        <TextBox Text="{Binding ElementName=textField,Path=Text}"/>
        <Image Source="{StaticResource Help.Icon}">
            <Image.ToolTip>
                <ToolTip Content="{Binding ElementName=textField,Path=HelpText}"/>
            </Image.ToolTip>
        </Image>
    </StackPanel>
</UserControl>

此代码显示工具提示，除了它是空的！此外，StaysOpen属性没有任何区别，因为工具提示在几秒钟后关闭。

This code does show the tooltip, except that it is empty! Also, the StaysOpen property does not make any difference as the tooltip shuts down after a few seconds.

有趣的是，当我直接在Image控件的工具提示属性绑定文本在工具提示弹出窗口中显示，但仍然不会保持打开状态：

Funny thing is that when I set the same binding directly on the Image control's ToolTip property the bound text is shown allright in the tooltip pop-up, however it still does not stay open:

<Image Source="{StaticResource Help.Icon}" ToolTip="{Binding ElementName=textField,Path=HelpText}">

所以我的问题是：

1. 如何绑定用户控件的HelpText依赖属性在第一个代码示例中不起作用，但在第二个代码示例中有效？_


2. 如何我使 ToolTip 保持开放，或者如何使 ToolTip 都保持打开并显示数据绑定文本？ / li>
   

1. How come the binding against the user control's HelpText dependency property does not work in the first code sample but does work in the second?
   
2. How do I make the ToolTip stay open or rather how do I make the ToolTip both stay open and show the databound text?

谢谢！

推荐答案

code>工具提示不是与其他XAML相同的VisualTree的一部分，所以 DataContext 不是继承自己的方式

ToolTips are not part of the same VisualTree as the rest of your XAML, so the DataContext is not inherited the way you would expect it to be.

写 ToolTip ={Binding SomeProperty}将自动设置ToolTip的 DataContext 到 SomeProperty ，但是如果您构建自定义工具提示，则必须自己执行此操作。

Writing ToolTip="{Binding SomeProperty}" will automatically set the ToolTip's DataContext to SomeProperty, however if you build a custom ToolTip you must do this yourself.

<ToolTip DataContext="{Binding PlacementTarget.DataContext,
        RelativeSource={RelativeSource Self}}" ... />

这将把ToolTip的 DataContext 绑定到

This will bind the ToolTip's DataContext to the DataContext of whatever object the ToolTip is on.

为了完成你想要做的工作，你的$ DataContext c $ c>< ToolTip> 可能看起来像这样，因为 PlaceTarget 将是您的图像：

To accomplish what you're trying to do, your <ToolTip> would probably look like this, since PlaceTarget would be your Image:

<!-- Could also use something like Tag if DataContext is actually used -->
<Image DataContext="{Binding ElementName=textField, Path=HelpText}"
       Source="{StaticResource Help.Icon}">
    <Image.ToolTip>
        <ToolTip Content="{Binding PlacementTarget.DataContext,
            RelativeSource={RelativeSource Self}}"/>
    </Image.ToolTip>
</Image>

至于为什么不会保持开放，我不积极，但可能是因为属性默认为5秒，这可能会覆盖 StaysOpen 属性。

As for why it won't stay open, I'm not positive but it might be because the ToolTipService.ShowDuration property defaults to 5 seconds, and that probably overwrites the StaysOpen property.

您可以尝试将其设置为更高的值，例如

You can try setting it to something higher, such as

<Image ToolTipService.ShowDuration="60000" ... />

或者您可以尝试使用 Popup 样式设计为 ToolTip 而不是。代码可能看起来像这样：

Or you can try this workaround of using a Popup styled to look like a ToolTip instead. The code would probably look something like this:

<Popup PlacementTarget="{Binding ElementName=MyImage}"
       IsOpen="{Binding IsMouseOver, ElementName=MyImage, Mode=OneWay}">
    <TextBlock Text="{Binding ElementName=textField, Path=HelpText}" />
</Popup>

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