Style "Cannot find resource 'MetroCheckBox'" in MahApps

Question

I'm starting to use styles in WPF. I'm using MahApps styles as a base, which so far has been really good. I've been able to make specific modifications using the BasedOn property.

One of the simpler changes is to add a default margin so when adding controls they don't touch. It's worked really well so far until I tried to use the MetroCheckBox. With this specific control it throws an xaml parse exception: "Cannot find resource named 'MetroCheckBox'. Resource names are case sensitive."

I had a look in the source code, trying to track down this issue and coppied the name directly from the GitHub:

https://github.com/MahApps/MahApps.Metro/blob/master/MahApps.Metro/Styles/Controls.CheckBox.xaml

It's definately and all my other controls work fine:

        <Style TargetType="{x:Type Button}" BasedOn="{StaticResource MetroButton}">
            <Setter Property="Margin" Value="2"/>
        </Style>

        <Style TargetType="{x:Type ComboBox}" BasedOn="{StaticResource MetroComboBox}">
            <Setter Property="Margin" Value="2"/>
        </Style>

        <Style TargetType="{x:Type CheckBox}" BasedOn="{StaticResource MetroCheckBox}">
            <Setter Property="Margin" Value="2"/>
        </Style>

        <Style TargetType="{x:Type TextBox}" BasedOn="{StaticResource MetroTextBox}">
            <Setter Property="Margin" Value="2"/>
        </Style>

Any ideas on how to fix this?

Note, I'm including the reference to the styles like so:

<Application
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:extra="http://schemas.extra.com/ui"
xmlns:system="clr-namespace:System;assembly=mscorlib"
xmlns:visualizationToolkit="clr-namespace:System.Windows.Controls.DataVisualization;assembly=System.Windows.Controls.DataVisualization.Toolkit"
xmlns:chartingToolkit="clr-namespace:System.Windows.Controls.DataVisualization.Charting;assembly=System.Windows.Controls.DataVisualization.Toolkit"
xmlns:Primitives="clr-namespace:System.Windows.Controls.DataVisualization.Charting.Primitives;assembly=System.Windows.Controls.DataVisualization.Toolkit"
xmlns:Themes="clr-namespace:Microsoft.Windows.Themes;assembly=PresentationFramework.Aero"
xmlns:Custom="http://metro.mahapps.com/winfx/xaml/controls"
x:Class="MyApp.App"
StartupUri="/MyApp;component/GUI/Window/Window3.xaml"
>

<Application.Resources>       
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Controls.xaml" />
            <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Fonts.xaml" />
            <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Colors.xaml" />
            <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Accents/Blue.xaml" />
            <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Accents/BaseDark.xaml" />
        </ResourceDictionary.MergedDictionaries>

        <Style TargetType="{x:Type Button}" BasedOn="{StaticResource MetroButton}">
            <Setter Property="Margin" Value="2"/>
        </Style>

        <Style TargetType="{x:Type ComboBox}" BasedOn="{StaticResource MetroComboBox}">
            <Setter Property="Margin" Value="2"/>
        </Style>

        <!--<Style TargetType="{x:Type CheckBox}" BasedOn="{StaticResource MetroCheckBox}">
            <Setter Property="Margin" Value="2"/>
        </Style>-->

        <Style TargetType="{x:Type TextBox}" BasedOn="{StaticResource MetroTextBox}">
            <Setter Property="Margin" Value="2"/>
        </Style>

        <!--Chart Style-->
        <Style TargetType="{x:Type chartingToolkit:Chart}
    ...
        </Style>

        <!--Top Tab Item-->
        <Style x:Key="TopTabItemStyle" TargetType="{x:Type TabItem}" BasedOn="{StaticResource {x:Type TabItem}}">
            ...
        </Style>

        <!--Tab Item-->
        <Style TargetType="{x:Type TabItem}" BasedOn="{StaticResource MetroTabItem}">
    ...
        </Style>

        <!-- Group Box-->
        <Style TargetType="{x:Type GroupBox}" BasedOn="{StaticResource MetroGroupBox}">
            <!--<Setter Property="Margin" Value="5"/>
            <Setter Property="Padding" Value="5"/>
            <Setter Property="Foreground" Value="{DynamicResource BlackBrush}"/>
            <Setter Property="Background" Value="{DynamicResource AccentColorBrush}"/>
            <Setter Property="BorderBrush" Value="{DynamicResource AccentColorBrush}"/>
            <Setter Property="Custom:ControlsHelper.HeaderFontSize" Value="{DynamicResource ContentFontSize}"/>
            <Setter Property="Custom:GroupBoxHelper.HeaderForeground" Value="{x:Null}"/>-->
            <Setter Property="Custom:ControlsHelper.HeaderFontWeight" Value="SemiBold"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type GroupBox}">
                        <Grid x:Name="GroupBoxRoot">
                            <Grid.RowDefinitions>
                                <RowDefinition Height="Auto"/>
                                <RowDefinition Height="*"/>
                            </Grid.RowDefinitions>
                            <Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="0,0,0,2" Background="Transparent" Grid.Row="0">
                                <ContentPresenter ContentTemplate="{TemplateBinding HeaderTemplate}" Content="{TemplateBinding Header}" ContentStringFormat="{TemplateBinding HeaderStringFormat}" ContentSource="Header" TextElement.FontWeight="{TemplateBinding Custom:ControlsHelper.HeaderFontWeight}" TextElement.FontStretch="{TemplateBinding Custom:ControlsHelper.HeaderFontStretch}" TextElement.FontSize="{TemplateBinding Custom:ControlsHelper.HeaderFontSize}" Margin="{TemplateBinding Padding}" RecognizesAccessKey="True"/>
                            </Border>
                            <Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="0" Background="Transparent" Grid.Row="1">
                                <ContentPresenter Cursor="{TemplateBinding Cursor}" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" Margin="{TemplateBinding Padding}"/>
                            </Border>
                        </Grid>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </ResourceDictionary>
</Application.Resources>

Answer 1

This can be caused if you upgrade from a version of MahApps prior to 2.0 to a more recent version.

For more details, see: mahapps.com: Migration to v2.0 - MahApps.Metro https://mahapps.com/docs/guides/migration-to-v2.0

Answer 2

I ran it today and it works fine:

        <Style TargetType="{x:Type ComboBox}" BasedOn="{StaticResource MetroComboBox}">
            <Setter Property="Margin" Value="2"/>
        </Style>

As far as I can tell I've changed nothing to do with the project or references.

However, in the last few days Visual Studio had corrupted somehow with the designer throwing exceptions left right and center, solution explorer failing to display anything (was fixed after clearing Component Model Cache) and NuGet failing to work for me to check the MahApps version.

So I set off the installer on a repair install, and now the style works fine.

I have no idea if these are connected... but they may be, so I'll leave this up as an answer in case anyone else comes across this same issue.

Answer 3

You are missing the required ResourceDictionary to bring in the styles for the MahApps. You can do by including the ResourceDictionary definition in the XAML of either the XAML file where you are composing your view or you can add it to the APP.XAML file - the later will give you better performance in the short term.

For example: here is the MahApps controls xaml included with other MahApps resource dictionaries, the controls xaml is the one you need in this case:

<Application x:Class="MyApp"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <Application.Resources>

        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>

                <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Controls.xaml" />
                <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Fonts.xaml" />
                <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Colors.xaml" />
                <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Accents/Blue.xaml" />
                <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Accents/BaseLight.xaml" />

            </ResourceDictionary.MergedDictionaries>

        </ResourceDictionary>       

    </Application.Resources>
</Application>