C# WPF - Customizing the color of checkbox checkmark and background

Question

How would I go about changing the checkmark color and background color of a checkbox?

I want the check mark icon change to white and the background color of the check mark would be light blue or something.

<ContextMenu.ItemContainerStyle>
    <Style TargetType="{x:Type MenuItem}">
        <Setter Property="Tag" Value="{Binding Target}"/>
        <Setter Property="Header" Value="{Binding ColumnName}" />
        <Setter Property="IsCheckable" Value="True" />
        <Setter Property="IsChecked" Value="{Binding IsVisible}" />
        <Setter Property="Command" Value="{Binding Source={StaticResource Proxy}, Path=Data.SettingCommand}" />
        <Setter Property="CommandParameter" Value="{Binding .}" />
        
        <Setter Property="FontFamily" Value="/Fonts/#Poppins"/>
        <Setter Property="FontWeight" Value="SemiBold"/>
        <Setter Property="BorderThickness" Value="0"/>
        <Setter Property="Background" Value="{DynamicResource Foreground}"/>
        <Setter Property="BorderBrush" Value="{DynamicResource LineBrush}"/>
        <Setter Property="BorderBrush" Value="{DynamicResource LineBrush}"/>
        <Setter Property="Foreground" Value="{DynamicResource Text}"/>

        <Style.Triggers>
            <Trigger Property="IsHighlighted" Value="True">
                <Setter Property="Foreground" Value="Black" />
            </Trigger>
        </Style.Triggers>
    </Style>
</ContextMenu.ItemContainerStyle>

Answer 1

If you have a look here you'll see the docs say:

To apply the same property settings to multiple CheckBox controls, use the Style property. You can modify the default ControlTemplate to give the control a unique appearance.

So it looks like we'll need to use a ControlTemplate to style the checkbox. If we look at the docs for creating and applying ControlTemplates we can see a small example with a button.

To define a template we create one like so:

<ControlTemplate x:Key="customCheckbox" TargetType="Checkbox">
</ControlTemplate>

And we can apply it to an element like so:

<Checkbox Template="{StaticResource customCheckbox}" />

This is the CustomTemplate that originally defines a Checkbox (from here):

<Style x:Key="{x:Type CheckBox}"
       TargetType="{x:Type CheckBox}">
  <Setter Property="SnapsToDevicePixels"
          Value="true" />
  <Setter Property="OverridesDefaultStyle"
          Value="true" />
  <Setter Property="FocusVisualStyle"
          Value="{DynamicResource CheckBoxFocusVisual}" />
  <Setter Property="Template">
    <Setter.Value>
      <ControlTemplate TargetType="{x:Type CheckBox}">
        <BulletDecorator Background="Transparent">
          <BulletDecorator.Bullet>
            <Border x:Name="Border"
                    Width="13"
                    Height="13"
                    CornerRadius="0"
                    BorderThickness="1">
              <Border.BorderBrush>
                <LinearGradientBrush StartPoint="0,0"
                                     EndPoint="0,1">
                  <LinearGradientBrush.GradientStops>
                    <GradientStopCollection>
                      <GradientStop Color="{DynamicResource BorderLightColor}"
                                    Offset="0.0" />
                      <GradientStop Color="{DynamicResource BorderDarkColor}"
                                    Offset="1.0" />
                    </GradientStopCollection>
                  </LinearGradientBrush.GradientStops>
                </LinearGradientBrush>
              </Border.BorderBrush>
              <Border.Background>
                <LinearGradientBrush StartPoint="0,0"
                                     EndPoint="0,1">
                  <LinearGradientBrush.GradientStops>
                    <GradientStopCollection>
                      <GradientStop Color="{DynamicResource ControlLightColor}" />
                      <GradientStop Color="{DynamicResource ControlMediumColor}"
                                    Offset="1.0" />
                    </GradientStopCollection>
                  </LinearGradientBrush.GradientStops>
                </LinearGradientBrush>

              </Border.Background>
              <Grid>
                <Path Visibility="Collapsed"
                      Width="7"
                      Height="7"
                      x:Name="CheckMark"
                      SnapsToDevicePixels="False"
                      StrokeThickness="2"
                      Data="M 0 0 L 7 7 M 0 7 L 7 0">
                  <Path.Stroke>
                    <SolidColorBrush Color="{DynamicResource GlyphColor}" />
                  </Path.Stroke>
                </Path>
                <Path Visibility="Collapsed"
                      Width="7"
                      Height="7"
                      x:Name="InderminateMark"
                      SnapsToDevicePixels="False"
                      StrokeThickness="2"
                      Data="M 0 7 L 7 0">
                  <Path.Stroke>
                    <SolidColorBrush Color="{DynamicResource GlyphColor}" />
                  </Path.Stroke>
                </Path>
              </Grid>
            </Border>
          </BulletDecorator.Bullet>
          <VisualStateManager.VisualStateGroups>
            <VisualStateGroup x:Name="CommonStates">
              <VisualState x:Name="Normal" />
              <VisualState x:Name="MouseOver">
                <Storyboard>
                  <ColorAnimationUsingKeyFrames Storyboard.TargetName="Border"
                                                Storyboard.TargetProperty="(Panel.Background).
                      (GradientBrush.GradientStops)[1].(GradientStop.Color)">
                    <EasingColorKeyFrame KeyTime="0"
                                         Value="{StaticResource ControlMouseOverColor}" />
                  </ColorAnimationUsingKeyFrames>
                </Storyboard>
              </VisualState>
              <VisualState x:Name="Pressed">
                <Storyboard>
                  <ColorAnimationUsingKeyFrames Storyboard.TargetName="Border"
                                                Storyboard.TargetProperty="(Panel.Background).
                      (GradientBrush.GradientStops)[1].(GradientStop.Color)">
                    <EasingColorKeyFrame KeyTime="0"
                                         Value="{StaticResource ControlPressedColor}" />
                  </ColorAnimationUsingKeyFrames>
                  <ColorAnimationUsingKeyFrames Storyboard.TargetName="Border"
                                                Storyboard.TargetProperty="(Border.BorderBrush).
                      (GradientBrush.GradientStops)[0].(GradientStop.Color)">
                    <EasingColorKeyFrame KeyTime="0"
                                         Value="{StaticResource PressedBorderDarkColor}" />
                  </ColorAnimationUsingKeyFrames>
                  <ColorAnimationUsingKeyFrames Storyboard.TargetName="Border"
                                                Storyboard.TargetProperty="(Border.BorderBrush).
                      (GradientBrush.GradientStops)[1].(GradientStop.Color)">
                    <EasingColorKeyFrame KeyTime="0"
                                         Value="{StaticResource PressedBorderLightColor}" />
                  </ColorAnimationUsingKeyFrames>
                </Storyboard>
              </VisualState>
              <VisualState x:Name="Disabled" />
            </VisualStateGroup>
            <VisualStateGroup x:Name="CheckStates">
              <VisualState x:Name="Checked">
                <Storyboard>
                  <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)"
                                                 Storyboard.TargetName="CheckMark">
                    <DiscreteObjectKeyFrame KeyTime="0"
                                            Value="{x:Static Visibility.Visible}" />
                  </ObjectAnimationUsingKeyFrames>
                </Storyboard>
              </VisualState>
              <VisualState x:Name="Unchecked" />
              <VisualState x:Name="Indeterminate">
                <Storyboard>
                  <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)"
                                                 Storyboard.TargetName="InderminateMark">
                    <DiscreteObjectKeyFrame KeyTime="0"
                                            Value="{x:Static Visibility.Visible}" />
                  </ObjectAnimationUsingKeyFrames>
                </Storyboard>
              </VisualState>
            </VisualStateGroup>
          </VisualStateManager.VisualStateGroups>
          <ContentPresenter Margin="4,0,0,0"
                            VerticalAlignment="Center"
                            HorizontalAlignment="Left"
                            RecognizesAccessKey="True" />
        </BulletDecorator>
      </ControlTemplate>
    </Setter.Value>
  </Setter>
</Style>

You should be able to pull out parts and add them to your custom ControlTemplate. I expect the parts you may be interested in are:

             <Grid>
                <Path Visibility="Collapsed"
                      Width="7"
                      Height="7"
                      x:Name="CheckMark"
                      SnapsToDevicePixels="False"
                      StrokeThickness="2"
                      Data="M 0 0 L 7 7 M 0 7 L 7 0">
                  <Path.Stroke>
                    <SolidColorBrush Color="{DynamicResource GlyphColor}" />
                  </Path.Stroke>
                </Path>
                <Path Visibility="Collapsed"
                      Width="7"
                      Height="7"
                      x:Name="InderminateMark"
                      SnapsToDevicePixels="False"
                      StrokeThickness="2"
                      Data="M 0 7 L 7 0">
                  <Path.Stroke>
                    <SolidColorBrush Color="{DynamicResource GlyphColor}" />
                  </Path.Stroke>
                </Path>
              </Grid>

Based on this answer to a similar stack over flow question.