How to make WPF Slider Thumb follow cursor from any point

问题

I have such slider:

<Slider Minimum="0" Maximum="100" 
TickFrequency="1"
IsMoveToPointEnabled="True"
IsSnapToTickEnabled="False"/>

I want to make next behavior: when MouseDown occured at any point of slider, Thumb not only moves once to that point, but also following cursor until MouseUp occurs.

Sorry if it was asked already, i couldn't find that question.

回答1:

This behavior will happen only when you drag the slider thumb itself, it is by design.

However, here's some code that will do it ;-)

Hook to the MouseMove event in XAML:

<Slider MouseMove="Slider_OnMouseMove" IsMoveToPointEnabled="True"/>

Then insert this code:

private void Slider_OnMouseMove(object sender, MouseEventArgs e)
{
    if (e.LeftButton == MouseButtonState.Pressed)
    {
        var slider = (Slider)sender;
        Point position = e.GetPosition(slider);
        double d = 1.0d / slider.ActualWidth * position.X;
        var p = slider.Maximum * d;
        slider.Value = p;
    }
}

Note :

You might have to take margins and padding of your slider into account should they differ, I haven't.
This was done on an horizontal slider.
Minimum value of my slider was 0, make sure to adjust the calculation should your minimum be negative.
Finally, it does seem to work only when IsMoveToPointEnabled is set.

回答2:

Aybe's solution works better in the thumb_MouseMove event.

void timelineThumb_MouseMove(object sender, MouseEventArgs e)
{

     if (e.LeftButton == MouseButtonState.Pressed)
     {
         var thumb = sender as Thumb;

         Point pos = e.GetPosition(uiVideoPlayerTimelineSlider);
         double d = 1.0d / uiVideoPlayerTimelineSlider.ActualWidth * pos.X;
         uiVideoPlayerTimelineSlider.Value = uiVideoPlayerTimelineSlider.Maximum * d;

     }
}

来源：https://stackoverflow.com/questions/15865734/how-to-make-wpf-slider-thumb-follow-cursor-from-any-point

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