WPF custom slider PART_SelectionRange lags behind the thumb

Question

I created custom sliders and a palette for my application. It works as expected, except for the rectangular rectangle PART_SelectionRange, which starts slightly behind the thumb, and by the time the maximum value is reached, it is noticeably behind it.

I do not know how this could be fixed, since it seems that the problem is the behavior of any class that controls the size of the PART_SelectionRange rectangle.

(Sorry, I do not know how to insert it).

<ControlTemplate x:Key="SliderThumbHorizontalDefault" TargetType="{x:Type Thumb}">
    <Grid>
        <!-- SliderThumb -->
        <Path x:Name="grip" Data="M-0.4,6.4 C1.2,1 9,1 10.5,6.5 12,11.787571 5.0267407,18.175417 5.0267407,18.175417 5.0267407,18.175417 -2,11.8 -0.4,6.4 z"
            Fill="White" Stretch="Fill" SnapsToDevicePixels="True"
            Stroke="Black" StrokeThickness="1" UseLayoutRounding="True" />
        <ContentPresenter Margin="0 4 0 0"  Content="{Binding Value, RelativeSource={RelativeSource AncestorType={x:Type Slider}}}" TextBlock.Foreground="Black" TextBlock.FontSize="20" TextBlock.TextAlignment="Center" />
    </Grid>
</ControlTemplate>

<ControlTemplate x:Key="SliderHorizontal" TargetType="{x:Type Slider}">
    <ControlTemplate.Resources>
        <vc:TickConverter x:Key="TickConverter" />
    </ControlTemplate.Resources>
    <Grid Height="{StaticResource SliderHeight}">
        <Border x:Name="TrackBackground" BorderBrush="{StaticResource SliderThumb.Track.Border}" BorderThickness="0"
                Background="White"
                CornerRadius="{Binding ActualHeight, Converter={StaticResource HalvingConverter}, ElementName=TrackBackground}">
            <!-- This rectangle is what lags behind! -->
            <Rectangle x:Name="PART_SelectionRange" Fill="SlateBlue"
                        HorizontalAlignment="Left" RadiusY="3" RadiusX="3" />
        </Border>
        <Track x:Name="PART_Track" >
            <Track.Thumb>
                <Thumb x:Name="Thumb" Focusable="False" Width="35" Height="47" OverridesDefaultStyle="True"
                            Template="{StaticResource SliderThumbHorizontalDefault}" Margin="-14.65,-55,-16,12"/>
            </Track.Thumb>
        </Track>
    </Grid>
    <ControlTemplate.Triggers>
        <Trigger Property="IsSelectionRangeEnabled" Value="true">
            <Setter Property="Visibility" TargetName="PART_SelectionRange" Value="Visible" />
        </Trigger>
        <Trigger Property="IsKeyboardFocused" Value="true">
            <Setter Property="Foreground" TargetName="Thumb" Value="Blue" />
        </Trigger>
    </ControlTemplate.Triggers>
</ControlTemplate>

<Style TargetType="{x:Type Slider}">
    <Setter Property="MinHeight" Value="{StaticResource SliderHeight}" />
    <Setter Property="MaxHeight" Value="{StaticResource SliderHeight}" />
    <Setter Property="Stylus.IsPressAndHoldEnabled" Value="false" />
    <Setter Property="IsSelectionRangeEnabled" Value="True" />
    <Setter Property="Background" Value="Transparent" />
    <Setter Property="BorderBrush" Value="Transparent" />
    <Setter Property="Foreground" Value="{StaticResource SliderThumb.Static.Foreground}" />
    <Setter Property="SelectionStart" Value="{Binding Minimum, RelativeSource={RelativeSource Self}}" />
    <Setter Property="SelectionEnd" Value="{Binding Value, RelativeSource={RelativeSource Self}}" />
    <Setter Property="Template" Value="{StaticResource SliderHorizontal}" />
</Style>

At this moment I do not know what I have to change. I believe that I tried to change every property that makes sense in xaml, so I think the problem is in the Slider class, but cannot figure out where.

Answer 1

, Slider Style ControlTemplate s.

, Slider Thumb. , "", Maximum. , Value, Thumb 0. , , , .

:

if (DoubleUtil.AreClose(range, 0d) || (DoubleUtil.AreClose(trackSize.Width, thumbSize.Width)))
{
    valueToSize = 0d;
}
else
{
    valueToSize = Math.Max(0.0, (trackSize.Width - thumbSize.Width) / range);
}

rangeElement.Width = ((SelectionEnd - SelectionStart) * valueToSize);
if (IsDirectionReversed)
{
    Canvas.SetLeft(rangeElement, (thumbSize.Width * 0.5) + Math.Max(Maximum - SelectionEnd, 0) * valueToSize);
}
else
{
    Canvas.SetLeft(rangeElement, (thumbSize.Width * 0.5) + Math.Max(SelectionStart - Minimum, 0) * valueToSize);
}

:

• , Thumb
• "PART_SelectionRange" ControlTemplate Binding IValueConverter ( Behavior s )

Answer 2

@dymanoid , ( ).

PART_SelectionRange ( ), .

<Border x:Name="TrackBackground" BorderBrush="{StaticResource SliderThumb.Track.Border}" BorderThickness="0"
        Background="{StaticResource SliderThumb.Track.Background}"
        CornerRadius="{Binding ActualHeight, Converter={StaticResource HalvingConverter}, ElementName=TrackBackground}">
    <Rectangle x:Name="SelectionRange" Fill="{StaticResource SliderThumb.Track.BackgroundSelected}"
                HorizontalAlignment="Left" RadiusY="3" RadiusX="3">
        <Rectangle.Width>
            <MultiBinding Converter="{StaticResource SliderToSelectionWidthConverter}">
                <Binding Path="Value" RelativeSource="{RelativeSource TemplatedParent}"/>
                <Binding Path="Maximum" RelativeSource="{RelativeSource TemplatedParent}"/>
                <Binding Path="Minimum" RelativeSource="{RelativeSource TemplatedParent}"/>
                <Binding Path="ActualWidth" RelativeSource="{RelativeSource TemplatedParent}"/>
            </MultiBinding>
        </Rectangle.Width>
    </Rectangle> 
</Border>

, Slider Value, Minimum, Maximum ActualWidth. :

class SliderToSelectionWidthConverter : IMultiValueConverter
{
    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
    {
        var Value = (double) values[0];
        var Minimum = (double) values[1];
        var Maximum = (double) values[2];
        var ActualWidth = (double) values[3];
        return (1 - (Value - Minimum) / (Maximum - Minimum)) * ActualWidth;
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

SelectionRange. .