How to show dialog box without needing a metro accent theme?

Question

I want to show a metro-style dialog box like so:

public async void Button_Click(object sender, RoutedEventArgs e)
{
   var metroWindow = (Application.Current.MainWindow as MetroWindow);
   await metroWindow.ShowMessageAsync("Title", "Body");
}

However, it kept throwing the error:

An unhandled exception of type 'System.NullReferenceException' occurred in mscorlib.dll

With the stack trace:

at MahApps.Metro.Controls.Dialogs.BaseMetroDialog.HandleTheme()

at MahApps.Metro.Controls.Dialogs.BaseMetroDialog.Initialize()

at MahApps.Metro.Controls.Dialogs.BaseMetroDialog..ctor(MetroWindow owningWindow, MetroDialogSettings settings)

...

at System.Threading.ThreadHelper.ThreadStart()

So after a lot of fiddling, I realized I needed to include an accent in my App.xaml resources to give it a color scheme.

<ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Accents/Cobalt.xaml" /> 

However, I've built my program without that and including it has messed with all my styling. Furthermore, there aren't many accents total see here and I can't find one that fits with my scheme.

I've been trying to give the ShowMessageAsync method it's own color scheme directly with commands such as

metroWindow.MetroDialogOptions.ColorScheme = MetroDialogOptions.ColorScheme 
// MetroDialogColorScheme.Theme 
// MetroDialogColorScheme.Accented 
// MetroDialogColorScheme.Inverted;

But the same error continues to appear. Is there some way to get around this? How could I get the dialog box to use my own style?

Edit

I've actually downloaded the file here: https://github.com/MahApps/MahApps.Metro/blob/master/MahApps.Metro/Styles/Accents/Cobalt.xaml

And in ResourceDirectory.MergedDictionaries replaced

  <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Accents/Cobalt.xaml" />

With

  <ResourceDictionary Source="Cobalt.xaml" />

And that's enough to break the function. I can see that that theme is still in effect, but when I try to trigger the dialog box, the window will fade but the dialog box doesn't appear and I need to restart the program. What's going on?

Answer 1

You should look at the ThemeManager. Set the AppStyle when your application start like so :

ThemeManager.ChangeAppStyle(this, ThemeManager.Accents.First(x => x.Name == "Red"), ThemeManager.DetectAppStyle().Item1);

Here is an example of theme avaible :

To use your own style you can add an accents like so :

ThemeManager.AddAccent("XpertdocBlue", new Uri("XpertdocBlue.xaml", UriKind.Relative));

Try to add a ResourceDictionary

Here is mine:

<controls:MetroWindow.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/BaseLight.xaml"/>
            <ResourceDictionary Source="pack://application:,,,/Xpertdoc.PortalWordAddIn.Views;component/Resources/Icons.xaml"/>
            <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Accents/BaseLight.xaml" />
            <ResourceDictionary Source="XpertdocBlue.xaml" />
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
</controls:MetroWindow.Resources>

And here is my Custom Accent (XpertdocBlue.xaml):

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <Color x:Key="HighlightColor">#FF2B579A</Color>

    <Color x:Key="AccentColor">#FF2B579A</Color>
    <!--60%-->
    <Color x:Key="AccentColor2">#CC2B579A</Color>
    <!--40%-->
    <Color x:Key="AccentColor3">#992B579A</Color>
    <!--20%-->
    <Color x:Key="AccentColor4">#662B579A</Color>

    <!-- re-set brushes too -->
    <SolidColorBrush x:Key="HighlightBrush" Color="{StaticResource HighlightColor}" />
    <SolidColorBrush x:Key="AccentColorBrush" Color="{StaticResource AccentColor}"/>
    <SolidColorBrush x:Key="AccentColorBrush2" Color="{StaticResource AccentColor2}"/>
    <SolidColorBrush x:Key="AccentColorBrush3" Color="{StaticResource AccentColor3}"/>
    <SolidColorBrush x:Key="AccentColorBrush4" Color="{StaticResource AccentColor4}"/>

    <SolidColorBrush x:Key="WindowTitleColorBrush" Color="{StaticResource AccentColor}" />

    <SolidColorBrush x:Key="AccentSelectedColorBrush" Color="White" />

    <LinearGradientBrush x:Key="ProgressBrush" EndPoint="0.001,0.5" StartPoint="1.002,0.5">
        <GradientStop Color="{StaticResource HighlightColor}" Offset="0" />
        <GradientStop Color="{StaticResource AccentColor3}" Offset="1" />
    </LinearGradientBrush>

    <SolidColorBrush x:Key="CheckmarkFill" Color="{StaticResource AccentColor}" />
    <SolidColorBrush x:Key="RightArrowFill" Color="{StaticResource AccentColor}" />

    <Color x:Key="IdealForegroundColor">White</Color>
    <SolidColorBrush x:Key="IdealForegroundColorBrush" Color="{StaticResource IdealForegroundColor}"/>

</ResourceDictionary>