MayShow/src/App.axaml

<Application xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             x:Class="MayShow.App"
             xmlns:viewModels="clr-namespace:MayShow.ViewModels"
             xmlns:views="clr-namespace:MayShow.Views"
             xmlns:dialogHostAvalonia="clr-namespace:DialogHostAvalonia;assembly=DialogHost.Avalonia"
             xmlns:behaviors="clr-namespace:DialogHostAvalonia;assembly=DialogHost.Avalonia"
             xmlns:helpers="clr-namespace:MayShow.Helpers"
             RequestedThemeVariant="Default"
             Name="MayShow">
    <Application.Styles>
        <FluentTheme />
        <StyleInclude Source="avares://AvaloniaProgressRing/Styles/ProgressRing.xaml"/>
        <StyleInclude Source="avares://Avalonia.Controls.DataGrid/Themes/Fluent.xaml"/>
        <dialogHostAvalonia:DialogHostStyles />
        <StyleInclude Source="avares://Xaml.Behaviors.Interactions.DragAndDrop/Styles.axaml" />
        <StyleInclude Source="avares://Xaml.Behaviors.Interactions.DragAndDrop.DataGrid/Styles.axaml" />

        <Style Selector="DataGrid.DragAndDrop">
            <Style.Resources>
                <helpers:DataGridDropHandler x:Key="DataGridDropHandler" />
            </Style.Resources>
            <Setter
                Property="RowHeaderWidth"
                Value="24" />
            <Setter Property="(Interaction.Behaviors)">
                <BehaviorCollectionTemplate>
                <BehaviorCollection>
                    <ContextDropBehavior Handler="{StaticResource DataGridDropHandler}" />
                </BehaviorCollection>
                </BehaviorCollectionTemplate>
            </Setter>
        </Style>

        <!-- This makes only the DataGridRowHeader available for dragging, instead of making the entire row draggable -->
        <!-- Which prevents a conflict between text selection in a cell and drag-and-drop -->
        <Style Selector="DataGrid.DragAndDrop DataGridRowHeader">
            <Setter Property="(Interaction.Behaviors)">
                <BehaviorCollectionTemplate>
                <BehaviorCollection>
                    <ContextDragBehavior HorizontalDragThreshold="3" VerticalDragThreshold="3" />
                </BehaviorCollection>
                </BehaviorCollectionTemplate>
            </Setter>
            <Setter Property="Content">
                <Template>
                <Image
                    Margin="12,0,12,0"
                    Width="12"
                    Height="12"
                    VerticalAlignment="Center"
                    HorizontalAlignment="Center">
                    <Image.Source>
                    <!-- Use your own image here, I used this: https://www.svgrepo.com/svg/347759/grabber -->
                    <DrawingImage Drawing="{StaticResource IconGrabber}" />
                    </Image.Source>
                </Image>
                </Template>
            </Setter>
        </Style>

        <Style Selector="DataGrid.ItemsDragAndDrop">
            <Style.Resources>
                <helpers:DataGridDropHandler x:Key="DataGridDropHandler" />
            </Style.Resources>
            <Setter Property="(Interaction.Behaviors)">
                <BehaviorCollectionTemplate>
                <BehaviorCollection>
                    <ContextDropBehavior Handler="{StaticResource DataGridDropHandler}" />
                </BehaviorCollection>
                </BehaviorCollectionTemplate>
            </Setter>
        </Style>
        <Style Selector="Button.Danger">
            <Setter Property="Foreground" Value="White"/>
            <Setter Property="Background" Value="#b00202"/>
            <Style Selector="^:pointerover /template/ ContentPresenter#PART_ContentPresenter">
                <Setter Property="Foreground" Value="White"/>
                <Setter Property="Background" Value="#bd0000"/>
            </Style>
            <Style Selector="^:pressed /template/ ContentPresenter#PART_ContentPresenter">
                <Setter Property="Foreground" Value="White"/>
                <Setter Property="Background" Value="#820202"/>
            </Style>
        </Style>
    </Application.Styles>
    <Application.DataTemplates>
        <DataTemplate DataType="{x:Type viewModels:MainViewModel}">
            <views:MainView/>
        </DataTemplate>
        <DataTemplate DataType="{x:Type viewModels:WarningDeleteItemViewModel}">
            <views:WarningDeleteItem/>
        </DataTemplate>
        <DataTemplate DataType="{x:Type viewModels:EditFileViewModel}">
            <views:EditFile/>
        </DataTemplate>
        <DataTemplate DataType="{x:Type viewModels:AboutViewModel}">
            <views:AboutView/>
        </DataTemplate>
        <DataTemplate DataType="{x:Type viewModels:WarningViewModel}">
            <views:WarningView/>
        </DataTemplate>
        <DataTemplate DataType="{x:Type viewModels:ShutdownCheckViewModel}">
            <views:ShutdownCheckView/>
        </DataTemplate>
        <DataTemplate DataType="{x:Type viewModels:ConfirmViewModel}">
            <views:ConfirmView/>
        </DataTemplate>
    </Application.DataTemplates>
    <Application.Resources>
        <ResourceDictionary>
            <helpers:DataGridDropHandler x:Key="DataGridDropHandler" />
            <ResourceDictionary.ThemeDictionaries>
                <ResourceDictionary x:Key='Light'>
                    <SolidColorBrush x:Key='DragDropBrush'>Black</SolidColorBrush>
                </ResourceDictionary>
                <ResourceDictionary x:Key='Dark'>
                    <SolidColorBrush x:Key='DragDropBrush'>White</SolidColorBrush>
                </ResourceDictionary>
            </ResourceDictionary.ThemeDictionaries>
            <!-- IconGrabber, MIT License, author: Primer, taken from: https://www.svgrepo.com/svg/347759/grabber -->
            <PathGeometry x:Key="IconGrabberGeometry">M15 18a1 1 0 100-2 1 1 0 000 2zm1-6a1 1 0 11-2 0 1 1 0 012 0zm-7 6a1 1 0 100-2 1 1 0 000 2zm0-5a1 1 0 100-2 1 1 0 000 2zm7-6a1 1 0 11-2 0 1 1 0 012 0zM9 8a1 1 0 100-2 1 1 0 000 2z</PathGeometry>
            <GeometryDrawing x:Key="IconGrabber" Brush="{DynamicResource DragDropBrush}" Geometry="{StaticResource IconGrabberGeometry}" />

            <FontFamily x:Key="FontAwesomeRegular">avares://MayShow/Assets/Fonts/FontAwesome/Font Awesome 7 Free-Regular-400.otf#Font Awesome 7 Free Regular</FontFamily>
            <FontFamily x:Key="FontAwesomeSolid">avares://MayShow/Assets/Fonts/FontAwesome/Font Awesome 7 Free-Solid-900.otf#Font Awesome 7 Free Solid</FontFamily>
        </ResourceDictionary>
    </Application.Resources>
    <NativeMenu.Menu>
        <NativeMenu>
            <NativeMenuItem Header="About ReceiptBuilder" Click="AboutOnClick" />
        </NativeMenu>
    </NativeMenu.Menu>
</Application>