Styling thumb using Blend

How can I style thumb using blend. I need to apply a cylinder like style to my thumb. with a gradient color effect. The gradient effect is to be applied vertically with a color combination of gray and white color. I have 0 knowledge in Blend Please help.

You can do it without using Blend. Simply add a slider in XAML page & open design view. Then right click on slider, open "Edit Template" menu and click on "Edit a Copy". So the default style of slider will be added in page's resource. Check out below given screenshot for it.

Now in style, you will see SliderThumbStyle. You can set thumb's template here. So I am giving you whole style with cylinder thumb having gradient effect.

<Style x:Key="SliderStyle1" TargetType="Slider">
    <Setter Property="Background" Value="{StaticResource SliderTrackBackgroundThemeBrush}"/>
    <Setter Property="BorderBrush" Value="{StaticResource SliderBorderThemeBrush}"/>
    <Setter Property="BorderThickness" Value="{StaticResource SliderBorderThemeThickness}"/>
    <Setter Property="Foreground" Value="{StaticResource SliderTrackDecreaseBackgroundThemeBrush}"/>
    <Setter Property="ManipulationMode" Value="None"/>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="Slider">
                <Grid Margin="{TemplateBinding Padding}">
                    <Grid.Resources>
                        <Style x:Key="SliderThumbStyle" TargetType="Thumb">
                            <Setter Property="BorderThickness" Value="1"/>
                            <Setter Property="BorderBrush" Value="{StaticResource SliderThumbBorderThemeBrush}"/>
                            <Setter Property="Background" Value="{StaticResource SliderThumbBackgroundThemeBrush}"/>
                            <Setter Property="Template">
                                <Setter.Value>
                                    <ControlTemplate TargetType="Thumb">
                                        <!--<Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}"/>-->
                                        <Canvas Margin="0 -5 0 0">
                                            <Path Width="20" Height="20" Canvas.Left="0" Canvas.Top="5" Stretch="Fill" StrokeLineJoin="Round" Stroke="#FF000000" Data="F1 M 177,190C 176.999,196.903 152.375,202.5 122,202.5C 91.6246,202.5 67.0006,196.903 67,189.979L 67,90L 177,90L 177,190 Z ">
                                                <Path.Fill>
                                                    <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                                                        <GradientStop Color="#FFBBACAC" Offset="0.527"/>
                                                        <GradientStop Color="White" Offset="1"/>
                                                    </LinearGradientBrush>
                                                </Path.Fill>
                                            </Path>
                                            <Path Width="20" Height="10" Canvas.Left="0" Canvas.Top="0" Stretch="Fill" StrokeLineJoin="Round" Stroke="#FF000000" Fill="#FFAC9E9E" Data="F1 M 122,77.4999C 152.376,77.4999 177,83.0964 177,89.9999C 177,96.9035 152.376,102.5 122,102.5C 91.6244,102.5 67.0001,96.9035 67.0001,89.9999C 67.0001,83.0964 91.6245,77.4999 122,77.4999 Z "/>
                                        </Canvas>
                                    </ControlTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </Grid.Resources>
                    <VisualStateManager.VisualStateGroups>
                        <VisualStateGroup x:Name="CommonStates">
                            <VisualState x:Name="Normal"/>
                            <VisualState x:Name="Pressed">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Fill" Storyboard.TargetName="HorizontalDecreaseRect">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderTrackDecreasePressedBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Fill" Storyboard.TargetName="HorizontalTrackRect">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderTrackPressedBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Fill" Storyboard.TargetName="VerticalDecreaseRect">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderTrackDecreasePressedBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Fill" Storyboard.TargetName="VerticalTrackRect">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderTrackPressedBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="HorizontalThumb">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderThumbPressedBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="HorizontalThumb">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderThumbPressedBorderThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="VerticalThumb">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderThumbPressedBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="VerticalThumb">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderThumbPressedBorderThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>
                            <VisualState x:Name="Disabled">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Stroke" Storyboard.TargetName="HorizontalBorder">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderDisabledBorderThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Stroke" Storyboard.TargetName="VerticalBorder">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderDisabledBorderThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Fill" Storyboard.TargetName="HorizontalDecreaseRect">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderTrackDecreaseDisabledBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Fill" Storyboard.TargetName="HorizontalTrackRect">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderTrackDisabledBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Fill" Storyboard.TargetName="VerticalDecreaseRect">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderTrackDecreaseDisabledBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Fill" Storyboard.TargetName="VerticalTrackRect">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderTrackDisabledBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="HorizontalThumb">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderThumbDisabledBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="HorizontalThumb">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderThumbDisabledBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="VerticalThumb">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderThumbDisabledBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="VerticalThumb">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderThumbDisabledBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Fill" Storyboard.TargetName="TopTickBar">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderTickMarkOutsideDisabledForegroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Fill" Storyboard.TargetName="HorizontalInlineTickBar">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderTickMarkInlineDisabledForegroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Fill" Storyboard.TargetName="BottomTickBar">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderTickMarkOutsideDisabledForegroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Fill" Storyboard.TargetName="LeftTickBar">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderTickMarkOutsideDisabledForegroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Fill" Storyboard.TargetName="VerticalInlineTickBar">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderTickMarkInlineDisabledForegroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Fill" Storyboard.TargetName="RightTickBar">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderTickMarkOutsideDisabledForegroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>
                            <VisualState x:Name="PointerOver">
                                <Storyboard>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Fill" Storyboard.TargetName="HorizontalDecreaseRect">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderTrackDecreasePointerOverBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Fill" Storyboard.TargetName="HorizontalTrackRect">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderTrackPointerOverBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Fill" Storyboard.TargetName="VerticalDecreaseRect">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderTrackDecreasePointerOverBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Fill" Storyboard.TargetName="VerticalTrackRect">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderTrackPointerOverBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="HorizontalThumb">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderThumbPointerOverBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="HorizontalThumb">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderThumbPointerOverBorderThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="VerticalThumb">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderThumbPointerOverBackgroundThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="VerticalThumb">
                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource SliderThumbPointerOverBorderThemeBrush}"/>
                                    </ObjectAnimationUsingKeyFrames>
                                </Storyboard>
                            </VisualState>
                        </VisualStateGroup>
                        <VisualStateGroup x:Name="FocusStates">
                            <VisualState x:Name="Focused">
                                <Storyboard>
                                    <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="FocusVisualWhiteHorizontal"/>
                                    <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="FocusVisualBlackHorizontal"/>
                                    <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="FocusVisualWhiteVertical"/>
                                    <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="FocusVisualBlackVertical"/>
                                </Storyboard>
                            </VisualState>
                            <VisualState x:Name="Unfocused"/>
                        </VisualStateGroup>
                    </VisualStateManager.VisualStateGroups>
                    <Grid x:Name="HorizontalTemplate" Background="Transparent">
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="Auto"/>
                            <ColumnDefinition Width="Auto"/>
                            <ColumnDefinition Width="*"/>
                        </Grid.ColumnDefinitions>
                        <Grid.RowDefinitions>
                            <RowDefinition Height="17"/>
                            <RowDefinition Height="Auto"/>
                            <RowDefinition Height="32"/>
                        </Grid.RowDefinitions>
                        <Rectangle x:Name="HorizontalTrackRect" Grid.ColumnSpan="3" Fill="{TemplateBinding Background}" Grid.Row="1"/>
                        <Rectangle x:Name="HorizontalDecreaseRect" Fill="{TemplateBinding Foreground}" Grid.Row="1"/>
                        <TickBar x:Name="TopTickBar" Grid.ColumnSpan="3" Fill="{StaticResource SliderTickmarkOutsideBackgroundThemeBrush}" Height="{StaticResource SliderOutsideTickBarThemeHeight}" Margin="0,0,0,2" Visibility="Collapsed" VerticalAlignment="Bottom"/>
                        <TickBar x:Name="HorizontalInlineTickBar" Grid.ColumnSpan="3" Fill="{StaticResource SliderTickMarkInlineBackgroundThemeBrush}" Height="{StaticResource SliderTrackThemeHeight}" Grid.Row="1" Visibility="Collapsed"/>
                        <TickBar x:Name="BottomTickBar" Grid.ColumnSpan="3" Fill="{StaticResource SliderTickmarkOutsideBackgroundThemeBrush}" Height="{StaticResource SliderOutsideTickBarThemeHeight}" Margin="0,2,0,0" Grid.Row="2" Visibility="Collapsed" VerticalAlignment="Top"/>
                        <Rectangle x:Name="HorizontalBorder" Grid.ColumnSpan="3" Grid.Row="1" Stroke="{TemplateBinding BorderBrush}" StrokeThickness="{TemplateBinding BorderThickness}"/>
                        <Thumb x:Name="HorizontalThumb" Background="{StaticResource SliderThumbBackgroundThemeBrush}" Grid.Column="1" DataContext="{TemplateBinding Value}" Height="{StaticResource SliderTrackThemeHeight}" Grid.Row="1" Style="{StaticResource SliderThumbStyle}" Width="{StaticResource SliderTrackThemeHeight}"/>
                        <Rectangle x:Name="FocusVisualWhiteHorizontal" Grid.ColumnSpan="3" IsHitTestVisible="False" Opacity="0" Grid.RowSpan="3" StrokeDashOffset="1.5" StrokeEndLineCap="Square" Stroke="{StaticResource FocusVisualWhiteStrokeThemeBrush}" StrokeDashArray="1,1"/>
                        <Rectangle x:Name="FocusVisualBlackHorizontal" Grid.ColumnSpan="3" IsHitTestVisible="False" Opacity="0" Grid.RowSpan="3" StrokeDashOffset="0.5" StrokeEndLineCap="Square" Stroke="{StaticResource FocusVisualBlackStrokeThemeBrush}" StrokeDashArray="1,1"/>
                    </Grid>
                    <Grid x:Name="VerticalTemplate" Background="Transparent" Visibility="Collapsed">
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="17"/>
                            <ColumnDefinition Width="Auto"/>
                            <ColumnDefinition Width="17"/>
                        </Grid.ColumnDefinitions>
                        <Grid.RowDefinitions>
                            <RowDefinition Height="*"/>
                            <RowDefinition Height="Auto"/>
                            <RowDefinition Height="Auto"/>
                        </Grid.RowDefinitions>
                        <Rectangle x:Name="VerticalTrackRect" Grid.Column="1" Fill="{TemplateBinding Background}" Grid.RowSpan="3"/>
                        <Rectangle x:Name="VerticalDecreaseRect" Grid.Column="1" Fill="{TemplateBinding Foreground}" Grid.Row="2"/>
                        <TickBar x:Name="LeftTickBar" Fill="{StaticResource SliderTickmarkOutsideBackgroundThemeBrush}" HorizontalAlignment="Right" Margin="0,0,2,0" Grid.RowSpan="3" Visibility="Collapsed" Width="{StaticResource SliderOutsideTickBarThemeHeight}"/>
                        <TickBar x:Name="VerticalInlineTickBar" Grid.Column="1" Fill="{StaticResource SliderTickMarkInlineBackgroundThemeBrush}" Grid.RowSpan="3" Visibility="Collapsed" Width="{StaticResource SliderTrackThemeHeight}"/>
                        <TickBar x:Name="RightTickBar" Grid.Column="2" Fill="{StaticResource SliderTickmarkOutsideBackgroundThemeBrush}" HorizontalAlignment="Left" Margin="2,0,0,0" Grid.RowSpan="3" Visibility="Collapsed" Width="{StaticResource SliderOutsideTickBarThemeHeight}"/>
                        <Rectangle x:Name="VerticalBorder" Grid.Column="1" Grid.RowSpan="3" Stroke="{TemplateBinding BorderBrush}" StrokeThickness="{TemplateBinding BorderThickness}"/>
                        <Thumb x:Name="VerticalThumb" Background="{StaticResource SliderThumbBackgroundThemeBrush}" Grid.Column="1" DataContext="{TemplateBinding Value}" Height="{StaticResource SliderTrackThemeHeight}" Grid.Row="1" Style="{StaticResource SliderThumbStyle}" Width="{StaticResource SliderTrackThemeHeight}"/>
                        <Rectangle x:Name="FocusVisualWhiteVertical" Grid.ColumnSpan="3" IsHitTestVisible="False" Opacity="0" Grid.RowSpan="3" StrokeDashOffset="1.5" StrokeEndLineCap="Square" Stroke="{StaticResource FocusVisualWhiteStrokeThemeBrush}" StrokeDashArray="1,1"/>
                        <Rectangle x:Name="FocusVisualBlackVertical" Grid.ColumnSpan="3" IsHitTestVisible="False" Opacity="0" Grid.RowSpan="3" StrokeDashOffset="0.5" StrokeEndLineCap="Square" Stroke="{StaticResource FocusVisualBlackStrokeThemeBrush}" StrokeDashArray="1,1"/>
                    </Grid>
                </Grid>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

<Slider Width="300" Maximum="100" Style="{StaticResource SliderStyle1}" />