Slider.Value不反映拖动滑块的Thumb元素 [英] Slider.Value doesn't reflect dragging of slider's Thumb element

问题描述

大家好！

我想将TextBlock的Text属性的值绑定到slider的Value属性。

I want to bind the value of TextBlock's Text property to slider's Value property.

一切似乎都很明显：我们需要使用这样的语法

Everything seems obvious : we need to use such syntax

        <Grid>
            <Slider x:Name="slider" HorizontalAlignment="Left" Margin="521,300,0,0" VerticalAlignment="Top" Width="618"/>
            <TextBlock x:Name="sliderValueTextBlock" HorizontalAlignment="Left" Margin="779,475,0,0" Text="{Binding ElementName=slider, Path=Value}" VerticalAlignment="Top"/>
        </Grid>

但是在启动应用程序后它很有趣：如果我拖动滑块的Thumb，实际上没有任何实际情况发生。没有对TextBlock的Text属性值进行任何更改。

But it goes interesting right after launching application : if I drag a slider's Thumb nothing actually happens. No changes are made to TextBlock's Text property value.

除此之外，我看到在拖动Thumb时，Thumb的ToolTip值始终等于0.

More than that, I see that while dragging the Thumb, value of Thumb's ToolTip is equal 0 all the time.

我进一步调查过 - 尝试过TwoWay绑定模式等但我唯一能做到的就是只有将这段代码放入Slider的ValueChanged事件处理程序时才能将TextBlock的Text属性equl的值设置为slider的Value：

I've investigated further - tried TwoWay binding mode etc. but the only thing I achieved is that I can set the value of TextBlock's Text property equl to slider's Value only if I put this code into Slider's ValueChanged event handler :

Slider slider = (Slider)sender;

if(slider != null)
{
this.sliderValueTextBlock.Text = slider.Value.ToString();
}

所以，对我而言，我不清楚为什么我不能直接从绑定中获取这些价值使用代码behing。

So, for me it's not clear why I can't get those value from binding directly instead of using code-behing.

我将不胜感激任何帮助。

I would appreciate any help.

非常感谢！

推荐答案

我测试了它并且它与我合作，绑定没问题，但我注意到你的文本块没有宽度和高度，这就是为什么你看不到它：D尝试下面的代码并告诉我它是否有效

i tested it and it worked with me, no problem in binding, but i noticed that your text block has no width and height, that is why you cannot see it :D try the following code and tell me if it worked

        <Slider x:Name="slider" HorizontalAlignment="Left" Margin="521,300,0,0" VerticalAlignment="Top" Width="618"/>
        <TextBlock x:Name="sliderValueTextBlock" HorizontalAlignment="Left" Margin="839,403,0,0" Text="{Binding ElementName=slider, Path=Value}" VerticalAlignment="Top" Height="56" Width="233"/>

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