CODEWITHSUNDEEP
c#wpfmahapps.metro
Beachwalker
Beachwalker

Reputation: 7915

Attaching Behaviour to MetroWindow fails and results in wrong Style

I have a simple test application that shows a simple Mahapps MetroWindow with an attached Behaviour. The problem is when attaching the Behaviour the outer border of the Mahapps MetroWindow is drawn.

enter image description here

<controls:MetroWindow x:Class="Desktop.Shell.Modern.ShellView"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:controls="http://metro.mahapps.com/winfx/xaml/controls"
        xmlns:cal="http://www.caliburnproject.org"
        xmlns:modern="clr-namespace:Desktop.Shell.Modern"
        xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
        Height="350"
        Width="525"
        ResizeMode="CanResizeWithGrip"
        WindowTransitionsEnabled="True"
        ShowIconOnTitleBar="False"
        TitleCaps="False"
        GlowBrush="{DynamicResource WindowTitleColorBrush}" >
    <i:Interaction.Behaviors>
        <modern:SomeBehavior SomeKey="{Binding Key}" />
    </i:Interaction.Behaviors>
    <ContentControl cal:View.Model="{Binding ActiveItem}" />
</controls:MetroWindow>

When removing the Behaviour everything looks as expected:

enter image description here

... but the Behaviour itself did nothing (yet). Here is the code of the SomeBehaviour class:

public sealed class SomeBehavior : Behavior<Window>
{
    public static readonly DependencyProperty SomeKeyProperty =
      DependencyProperty.Register(
        "SomeKey",
        typeof(Key),
        typeof(SomeBehavior),
        new PropertyMetadata(default(Key)));

    public Key SomeKey
    {
        get
        {
            return (Key)this.GetValue(SomeKeyProperty);
        }

        set
        {
            this.SetValue(SomeKeyProperty, value);
        }
    }

    protected override void OnAttached()
    {
        base.OnAttached();

    }

    protected override void OnDetaching()
    {
        base.OnDetaching();
    }
}

Am I doing something wrong? Should I attach the Behaviour in a different way than attaching them to "normal" Windows?

Upvotes: 5

Views: 1138

Answers (1)

Thomas Freudenberg
Thomas Freudenberg

Reputation: 5078

That's because Mahapps.Metro sets its required behaviours in the window style, see MetroWindow.xaml.

If you want to attach additional behaviors, you have to copy these behaviours to your window, e.g.

<controls:MetroWindow x:Class="Desktop.Shell.Modern.ShellView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:controls="http://metro.mahapps.com/winfx/xaml/controls"
    xmlns:cal="http://www.caliburnproject.org"
    xmlns:modern="clr-namespace:Desktop.Shell.Modern"
    xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
    xmlns:Behaviours="http://metro.mahapps.com/winfx/xaml/shared"
    Height="350"
    Width="525"
    ResizeMode="CanResizeWithGrip"
    WindowTransitionsEnabled="True"
    ShowIconOnTitleBar="False"
    TitleCaps="False"
    GlowBrush="{DynamicResource WindowTitleColorBrush}" >
    <i:Interaction.Behaviors>
        <modern:SomeBehavior SomeKey="{Binding Key}" />
        <Behaviours:BorderlessWindowBehavior />
        <Behaviours:WindowsSettingBehaviour />
        <Behaviours:GlowWindowBehavior />
    </i:Interaction.Behaviors>
    <ContentControl cal:View.Model="{Binding ActiveItem}" />
</controls:MetroWindow>

Upvotes: 5

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