Walleby/Wallet.Avalonia/DateEntryView.axaml

<SettingsExpander
    x:Class="Wallet.Avalonia.DateEntryView"
    xmlns="https://github.com/avaloniaui"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:vm="using:Wallet"
    x:DataType="vm:DateEntryViewModel"
    Header="{Binding Key}"
    IsExpanded="False">
    <SettingsExpander.Resources>
        <ResourceDictionary>
            <ResourceDictionary.ThemeDictionaries>
                <ResourceDictionary x:Key="Light">
                    <StaticResource x:Key="DatePickerButtonBorderBrush" ResourceKey="ControlStrokeColorDefaultBrush" />
                    <StaticResource x:Key="DatePickerButtonBorderBrushPointerOver" ResourceKey="ControlStrokeColorDefaultBrush" />
                </ResourceDictionary>
                <ResourceDictionary x:Key="Dark">
                    <StaticResource x:Key="DatePickerButtonBorderBrush" ResourceKey="SubtleFillColorTransparentBrush" />
                    <StaticResource x:Key="DatePickerButtonBorderBrushPointerOver" ResourceKey="SubtleFillColorTransparentBrush" />
                </ResourceDictionary>
            </ResourceDictionary.ThemeDictionaries>
        </ResourceDictionary>
        <Thickness x:Key="ButtonMargin">0,0,12,0</Thickness>
        <Thickness x:Key="ButtonPadding">0</Thickness>
        <x:Double x:Key="ButtonMinWidth">32</x:Double>
        <x:Double x:Key="ButtonMinHeight">32</x:Double>
        <Thickness x:Key="TextControlMargin">0</Thickness>
        <Thickness x:Key="TextControlPadding">10,6,6,5</Thickness>
        <Thickness x:Key="TextControlCompactPadding">0</Thickness>
        <Thickness x:Key="TextControlCompactMargin">0</Thickness>
        <Thickness x:Key="DatePickerHostPadding">0,5,0,6</Thickness>
        <Thickness x:Key="DatePickerHostMonthPadding">9,5,0,6</Thickness>
    </SettingsExpander.Resources>
    <SettingsExpander.Styles>
        <Style Selector="SettingsExpander.Write">
            <Style Selector="^ /template/ SettingsExpanderItem#ContentHost">
                <Style Selector="^ /template/ ContentPresenter#FooterPresenter">
                    <Setter Property="MinWidth" Value="{Binding Width}" />
                </Style>
                <Style Selector="^:footerBottom /template/ ContentPresenter#FooterPresenter">
                    <Setter Property="HorizontalAlignment" Value="Stretch" />
                    <Setter Property="MinWidth" Value="0" />
                </Style>
            </Style>
            <Style Selector="^ DatePicker">
                <Setter Property="MaxWidth" Value="{Binding Width}" />
                <Setter Property="MinWidth" Value="{Binding Width}" />
                <Setter Property="IsVisible" Value="True" />
                <Setter Property="Height" Value="32" />
            </Style>
            <Style Selector="^ TextBox">
                <Setter Property="IsVisible" Value="False" />
            </Style>
        </Style>
        <Style Selector="SettingsExpander.Read">
            <Style Selector="^ /template/ SettingsExpanderItem#ContentHost">
                <Style Selector="^ /template/ ContentPresenter#FooterPresenter">
                    <Setter Property="MinWidth" Value="0" />
                </Style>
                <Style Selector="^:footerBottom /template/ ContentPresenter#FooterPresenter">
                    <Setter Property="HorizontalAlignment" Value="Stretch" />
                    <Setter Property="MinWidth" Value="0" />
                </Style>
            </Style>
            <Style Selector="^ TextBox">
                <Setter Property="MinWidth" Value="0" />
                <Setter Property="IsReadOnly" Value="True" />
                <Setter Property="BorderBrush" Value="Transparent" />
                <Setter Property="BorderThickness" Value="0" />
                <Setter Property="Background" Value="Transparent" />
                <Setter Property="Margin" Value="{StaticResource TextControlCompactMargin}" />
                <Setter Property="Padding" Value="{StaticResource TextControlCompactPadding}" />
                <Setter Property="MinHeight" Value="0" />
                <Setter Property="TextWrapping" Value="NoWrap" />
                <Setter Property="Foreground">
                    <Setter.Value>
                        <SolidColorBrush Opacity="0.7" Color="{DynamicResource TextFillColorPrimary}" />
                    </Setter.Value>
                </Setter>
                <Style Selector="^:pointerover">
                    <Setter Property="Foreground">
                        <Setter.Value>
                            <SolidColorBrush Opacity="0.7" Color="{DynamicResource TextFillColorPrimary}" />
                        </Setter.Value>
                    </Setter>
                    <Style Selector="^ /template/ Border#PART_BorderElement">
                        <Setter Property="BorderBrush" Value="Transparent" />
                        <Setter Property="Background" Value="Transparent" />
                    </Style>
                </Style>
                <Style Selector="^:focus">
                    <Setter Property="Foreground">
                        <Setter.Value>
                            <SolidColorBrush Opacity="0.7" Color="{DynamicResource TextFillColorPrimary}" />
                        </Setter.Value>
                    </Setter>
                    <Style Selector="^ /template/ Border#PART_BorderElement">
                        <Setter Property="Background" Value="Transparent" />
                        <Setter Property="BorderBrush" Value="Transparent" />
                    </Style>
                </Style>
            </Style>
            <Style Selector="^ DatePicker">
                <Setter Property="MinWidth" Value="0" />
                <Setter Property="MinHeight" Value="0" />
                <Setter Property="IsVisible" Value="False" />
            </Style>
        </Style>
    </SettingsExpander.Styles>
    <Interaction.Behaviors>
        <DataTriggerBehavior Binding="{Binding State}" Value="{x:Static vm:ItemState.Read}">
            <AddClassAction ClassName="Read" RemoveIfExists="True" />
            <RemoveClassAction ClassName="Write" />
        </DataTriggerBehavior>
        <DataTriggerBehavior Binding="{Binding State}" Value="{x:Static vm:ItemState.New}">
            <AddClassAction ClassName="Write" RemoveIfExists="True" />
            <RemoveClassAction ClassName="Read" />
        </DataTriggerBehavior>
        <DataTriggerBehavior Binding="{Binding State}" Value="{x:Static vm:ItemState.Write}">
            <AddClassAction ClassName="Write" RemoveIfExists="True" />
            <RemoveClassAction ClassName="Read" />
        </DataTriggerBehavior>
    </Interaction.Behaviors>
    <SettingsExpander.Icon>
        <Button
            Grid.Column="1"
            MinWidth="{StaticResource ButtonMinWidth}"
            MinHeight="{StaticResource ButtonMinHeight}"
            Margin="{StaticResource ButtonMargin}"
            Padding="{StaticResource ButtonPadding}"
            HorizontalContentAlignment="Center"
            VerticalContentAlignment="Center"
            Command="{Binding RemoveCommand}"
            Theme="{StaticResource TransparentButton}">
            <Viewbox Height="20">
                <TextBlock
                    HorizontalAlignment="Center"
                    VerticalAlignment="Center"
                    FontFamily="{StaticResource FluentThemeFontFamily}"
                    FontSize="16"
                    Text="&#xED75;" />
            </Viewbox>
            <Button.Styles>
                <Style Selector="Button.Hide">
                    <Setter Property="IsVisible" Value="True" />
                </Style>
                <Style Selector="Button.Show">
                    <Setter Property="IsVisible" Value="False" />
                </Style>
            </Button.Styles>
            <Interaction.Behaviors>
                <DataTriggerBehavior Binding="{Binding State}" Value="{x:Static vm:ItemState.Read}">
                    <AddClassAction ClassName="Show" RemoveIfExists="True" />
                    <RemoveClassAction ClassName="Hide" />
                </DataTriggerBehavior>
                <DataTriggerBehavior Binding="{Binding State}" Value="{x:Static vm:ItemState.New}">
                    <AddClassAction ClassName="Hide" RemoveIfExists="True" />
                    <RemoveClassAction ClassName="Show" />
                </DataTriggerBehavior>
                <DataTriggerBehavior Binding="{Binding State}" Value="{x:Static vm:ItemState.Write}">
                    <AddClassAction ClassName="Hide" RemoveIfExists="True" />
                    <RemoveClassAction ClassName="Show" />
                </DataTriggerBehavior>
            </Interaction.Behaviors>
        </Button>
    </SettingsExpander.Icon>
    <SettingsExpander.Action>
        <ItemEntryActionView />
    </SettingsExpander.Action>
    <SettingsExpander.Footer>
        <Grid>
            <DatePicker SelectedDate="{Binding Value}" />
            <TextBox Text="{Binding Value, StringFormat=d}" />
        </Grid>
    </SettingsExpander.Footer>
</SettingsExpander>