C# - Changing color of checkmark in checkbox

Question

I have a C# application with a tick checkmark when user select the checkbox. The default color is black and not set by anyone. I would like to know the best approach to use to change the color of the checkmark, say to red instead of black.

I can't seem to find which part of the code is responsible for the color change. Tried finding resources online but it requires writing over hundred of lines of XAML just to set the color.

Any suggestion please.

EDIT:

<Setter.Value>
                    <ControlTemplate TargetType="{x:Type CheckBox}">
                        <Grid x:Name="templateRoot" Background="Transparent" SnapsToDevicePixels="True">
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="Auto"/>
                                <ColumnDefinition Width="*"/>
                            </Grid.ColumnDefinitions>
                            <Border x:Name="checkBoxBorder" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="1" VerticalAlignment="{TemplateBinding VerticalContentAlignment}">
                                <Grid x:Name="markGrid">
                                    <Path x:Name="optionMark" Data="F1 M 9.97498,1.22334L 4.6983,9.09834L 4.52164,9.09834L 0,5.19331L 1.27664,3.52165L 4.255,6.08833L 8.33331,1.52588e-005L 9.97498,1.22334 Z " Fill="{StaticResource OptionMark.Static.Glyph}" Margin="1" Opacity="0" Stretch="None"/>
                                    <Rectangle x:Name="indeterminateMark" Fill="{StaticResource OptionMark.Static.Glyph}" Margin="2" Opacity="0"/>
                                </Grid>
                            </Border>
                            <ContentPresenter x:Name="contentPresenter" Grid.Column="1" Focusable="False" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
                        </Grid>
                        <ControlTemplate.Triggers>
                            <Trigger Property="HasContent" Value="true">
                                <Setter Property="FocusVisualStyle" Value="{StaticResource OptionMarkFocusVisual}"/>
                                <Setter Property="Padding" Value="4,-1,0,0"/>
                            </Trigger>
                            <Trigger Property="IsMouseOver" Value="false">
                                <Setter Property="Background" TargetName="checkBoxBorder" Value="{StaticResource OptionMark.MouseOver.Background}"/>
                                <Setter Property="BorderBrush" TargetName="checkBoxBorder" Value="{StaticResource OptionMark.MouseOver.Border}"/>
                                <Setter Property="Fill" TargetName="optionMark" Value="{StaticResource OptionMark.MouseOver.Glyph}"/>
                                <Setter Property="Fill" TargetName="indeterminateMark" Value="{StaticResource OptionMark.MouseOver.Glyph}"/>
                            </Trigger>
                            <Trigger Property="IsEnabled" Value="false">
                                <Setter Property="Background" TargetName="checkBoxBorder" Value="{StaticResource OptionMark.Disabled.Background}"/>
                                <Setter Property="BorderBrush" TargetName="checkBoxBorder" Value="{StaticResource OptionMark.Disabled.Border}"/>
                                <Setter Property="Fill" TargetName="optionMark" Value="{StaticResource OptionMark.Disabled.Glyph}"/>
                                <Setter Property="Fill" TargetName="indeterminateMark" Value="{StaticResource OptionMark.Disabled.Glyph}"/>
                            </Trigger>

                            <Trigger Property="IsChecked" Value="true">

                                <Setter Property="Opacity" TargetName="optionMark" Value="1" />
                                <Setter Property="Opacity" TargetName="indeterminateMark" Value="0"/>
                            </Trigger>
                            <Trigger Property="IsChecked" Value="{x:Null}" >
                                <Setter Property="Opacity" TargetName="optionMark" Value="0"/>
                                <Setter Property="Opacity" TargetName="indeterminateMark" Value="1"/>
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>

Answer 1

For anyone who needs a simple CheckBox Template

<Style x:Key="CheckBoxStyle" TargetType="CheckBox">
    <Setter Property="HorizontalAlignment" Value="Center"/>
    <Setter Property="VerticalAlignment" Value="Center"/>
    <Setter Property="Background" Value="Green"/>
    <Setter Property="Foreground" Value="Transparent"/>
    
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate>
                <Border BorderBrush="White" BorderThickness="1">
                    <Grid Width="15" Height="15" >
                        <Rectangle Fill="{TemplateBinding Background}"/>
                        <TextBlock Foreground="{TemplateBinding Foreground}" Margin="0 0 0 1" VerticalAlignment="Center" HorizontalAlignment="Center" Text="√"/>
                    </Grid>
                </Border>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
    
    <Style.Triggers>
        <Trigger Property="IsChecked" Value="True">
            <Setter Property="Foreground" Value="White"/>
        </Trigger>

        <Trigger Property="IsMouseOver" Value="True">
            <Setter Property="Background" Value="Red"/>
        </Trigger>
    </Style.Triggers>
</Style>

Answer 2

I understand that you want to avoid writing over hundered of lines of XAML just to set the color, but from Visual Studio 2012 onwards, there's a feature where you can edit a copy of the control template. In Design mode, right click on the checkbox control, select Edit Template > Edit A Copy...

Then you can set where to define the template at, so you could either reuse it or just use it for one checkbox.

These are the colors you need to manipulate if you're on Windows 8 or above since the template varies base on Windows version. (The generated template has the following code)

<CheckBox.Resources>
    <Style x:Key="FocusVisual">
        <Setter Property="Control.Template">
            <Setter.Value>
                <ControlTemplate>
                    <Rectangle Margin="2" SnapsToDevicePixels="true" Stroke="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" StrokeThickness="1" StrokeDashArray="1 2"/>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
    <SolidColorBrush x:Key="OptionMark.Static.Background" Color="#FFFFFFFF"/>
    <SolidColorBrush x:Key="OptionMark.Static.Border" Color="#FF707070"/>
    <Style x:Key="OptionMarkFocusVisual">
        <Setter Property="Control.Template">
            <Setter.Value>
                <ControlTemplate>
                    <Rectangle Margin="14,0,0,0" SnapsToDevicePixels="true" Stroke="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" StrokeThickness="1" StrokeDashArray="1 2"/>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
    <SolidColorBrush x:Key="OptionMark.MouseOver.Background" Color="#FFF3F9FF"/>
    <SolidColorBrush x:Key="OptionMark.MouseOver.Border" Color="#FF5593FF"/>
    <SolidColorBrush x:Key="OptionMark.MouseOver.Glyph" Color="#FF212121"/>
    <SolidColorBrush x:Key="OptionMark.Disabled.Background" Color="#FFE6E6E6"/>
    <SolidColorBrush x:Key="OptionMark.Disabled.Border" Color="#FFBCBCBC"/>
    <SolidColorBrush x:Key="OptionMark.Disabled.Glyph" Color="#FF707070"/>
    <SolidColorBrush x:Key="OptionMark.Pressed.Background" Color="#FFD9ECFF"/>
    <SolidColorBrush x:Key="OptionMark.Pressed.Border" Color="#FF3C77DD"/>
    <SolidColorBrush x:Key="OptionMark.Pressed.Glyph" Color="#FF212121"/>
    <SolidColorBrush x:Key="OptionMark.Static.Glyph" Color="#FF212121"/>
    <Style x:Key="CheckBoxStyleCustom" TargetType="{x:Type CheckBox}">
        <Setter Property="FocusVisualStyle" Value="{StaticResource FocusVisual}"/>
        <Setter Property="Background" Value="{StaticResource OptionMark.Static.Background}"/>
        <Setter Property="BorderBrush" Value="{StaticResource OptionMark.Static.Border}"/>
        <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
        <Setter Property="BorderThickness" Value="1"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type CheckBox}">
                    <Grid x:Name="templateRoot" Background="Transparent" SnapsToDevicePixels="True">
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="Auto"/>
                            <ColumnDefinition Width="*"/>
                        </Grid.ColumnDefinitions>
                        <Border x:Name="checkBoxBorder" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="1" VerticalAlignment="{TemplateBinding VerticalContentAlignment}">
                            <Grid x:Name="markGrid">
                                <Path x:Name="optionMark" Data="F1 M 9.97498,1.22334L 4.6983,9.09834L 4.52164,9.09834L 0,5.19331L 1.27664,3.52165L 4.255,6.08833L 8.33331,1.52588e-005L 9.97498,1.22334 Z " Fill="{StaticResource OptionMark.Static.Glyph}" Margin="1" Opacity="0" Stretch="None"/>
                                <Rectangle x:Name="indeterminateMark" Fill="{StaticResource OptionMark.Static.Glyph}" Margin="2" Opacity="0"/>
                            </Grid>
                        </Border>
                        <ContentPresenter x:Name="contentPresenter" Grid.Column="1" Focusable="False" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
                    </Grid>
                    <ControlTemplate.Triggers>
                        <Trigger Property="HasContent" Value="true">
                            <Setter Property="FocusVisualStyle" Value="{StaticResource OptionMarkFocusVisual}"/>
                            <Setter Property="Padding" Value="4,-1,0,0"/>
                        </Trigger>
                        <Trigger Property="IsMouseOver" Value="true">
                            <Setter Property="Background" TargetName="checkBoxBorder" Value="{StaticResource OptionMark.MouseOver.Background}"/>
                            <Setter Property="BorderBrush" TargetName="checkBoxBorder" Value="{StaticResource OptionMark.MouseOver.Border}"/>
                            <Setter Property="Fill" TargetName="optionMark" Value="{StaticResource OptionMark.MouseOver.Glyph}"/>
                            <Setter Property="Fill" TargetName="indeterminateMark" Value="{StaticResource OptionMark.MouseOver.Glyph}"/>
                        </Trigger>
                        <Trigger Property="IsEnabled" Value="false">
                            <Setter Property="Background" TargetName="checkBoxBorder" Value="{StaticResource OptionMark.Disabled.Background}"/>
                            <Setter Property="BorderBrush" TargetName="checkBoxBorder" Value="{StaticResource OptionMark.Disabled.Border}"/>
                            <Setter Property="Fill" TargetName="optionMark" Value="{StaticResource OptionMark.Disabled.Glyph}"/>
                            <Setter Property="Fill" TargetName="indeterminateMark" Value="{StaticResource OptionMark.Disabled.Glyph}"/>
                        </Trigger>
                        <Trigger Property="IsPressed" Value="true">
                            <Setter Property="Background" TargetName="checkBoxBorder" Value="{StaticResource OptionMark.Pressed.Background}"/>
                            <Setter Property="BorderBrush" TargetName="checkBoxBorder" Value="{StaticResource OptionMark.Pressed.Border}"/>
                            <Setter Property="Fill" TargetName="optionMark" Value="{StaticResource OptionMark.Pressed.Glyph}"/>
                            <Setter Property="Fill" TargetName="indeterminateMark" Value="{StaticResource OptionMark.Pressed.Glyph}"/>
                        </Trigger>
                        <Trigger Property="IsChecked" Value="true">
                            <Setter Property="Opacity" TargetName="optionMark" Value="1"/>
                            <Setter Property="Opacity" TargetName="indeterminateMark" Value="0"/>
                        </Trigger>
                        <Trigger Property="IsChecked" Value="{x:Null}">
                            <Setter Property="Opacity" TargetName="optionMark" Value="0"/>
                            <Setter Property="Opacity" TargetName="indeterminateMark" Value="1"/>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</CheckBox.Resources>

Edit: The ones that you have to modify to change the Check symbol colors are:

<SolidColorBrush x:Key="OptionMark.MouseOver.Glyph" Color="#FF212121"/>
<SolidColorBrush x:Key="OptionMark.Disabled.Glyph" Color="#FF707070"/>
<SolidColorBrush x:Key="OptionMark.Pressed.Glyph" Color="#FF212121"/>
<SolidColorBrush x:Key="OptionMark.Static.Glyph" Color="#FF212121"/>