WPF Button сontrol with automatic start of the timer command via a trigger

Generic.xaml

<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:controls="clr-namespace:WPFUserControls.Controls">

    <!--#region Static Resources -->
    <SolidColorBrush x:Key="Button.Static.Background" Color="#FFDDDDDD"/>
    <SolidColorBrush x:Key="Button.Static.Border" Color="#FF707070"/>
    <SolidColorBrush x:Key="Button.MouseOver.Background" Color="#FFBEE6FD"/>
    <SolidColorBrush x:Key="Button.MouseOver.Border" Color="#FF3C7FB1"/>
    <SolidColorBrush x:Key="Button.Pressed.Background" Color="#FFC4E5F6"/>
    <SolidColorBrush x:Key="Button.Pressed.Border" Color="#FF2C628B"/>
    <SolidColorBrush x:Key="Button.Disabled.Background" Color="#FFF4F4F4"/>
    <SolidColorBrush x:Key="Button.Disabled.Border" Color="#FFADB2B5"/>
    <SolidColorBrush x:Key="Button.Disabled.Foreground" Color="#FF838383"/>
    <!--#endregion-->

    <!--#region TimerButton.TimerTextBlock Style -->
    <Style x:Key="TimerButton.TimerTextBlockStyle" TargetType="TextBlock">
        <Setter Property="Visibility" Value="Collapsed"/>
    </Style>
    <!--#endregion-->

    <!--#region Focus visual style-->
    <Style x:Key="FocusVisual">
        <Setter Property="Control.Template">
            <Setter.Value>
                <ControlTemplate>
                    <Rectangle Margin="2" StrokeDashArray="1 2" SnapsToDevicePixels="true" StrokeThickness="1" Stroke="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
    <!--#endregion-->

    <!--#region TimerButton style -->
    <Style TargetType="{x:Type controls:TimerButton}">
        <Setter Property="FocusVisualStyle" Value="{StaticResource FocusVisual}"/>
        <Setter Property="Background" Value="{StaticResource Button.Static.Background}"/>
        <Setter Property="BorderBrush" Value="{StaticResource Button.Static.Border}"/>
        <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
        <Setter Property="BorderThickness" Value="1"/>
        <Setter Property="HorizontalContentAlignment" Value="Center"/>
        <Setter Property="VerticalContentAlignment" Value="Center"/>
        <Setter Property="Padding" Value="1"/>
        <Setter Property="TimerStart" Value="False"/>
        <Setter Property="TimerTextBlockStyle" Value="{StaticResource TimerButton.TimerTextBlockStyle}"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type controls:TimerButton}">
                    <Border x:Name="border" 
                                Background="{TemplateBinding Background}" 
                                BorderThickness="{TemplateBinding BorderThickness}" 
                                BorderBrush="{TemplateBinding BorderBrush}" 
                                SnapsToDevicePixels="true">
                        <DockPanel>
                            <TextBlock DockPanel.Dock="Right"
                                       x:Name="timerText"
                                       Text="{Binding TimerSeconds, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type controls:TimerButton}}}"
                                       Foreground="{TemplateBinding Foreground}"
                                       Background="{TemplateBinding Background}"
                                       FontFamily="{TemplateBinding FontFamily}"
                                       FontSize="{TemplateBinding FontSize}"
                                       FontWeight="{TemplateBinding FontWeight}"
                                       Margin="10,0"
                                       HorizontalAlignment="Left"
                                       VerticalAlignment="Center"
                                       Style="{TemplateBinding TimerTextBlockStyle}">
                            </TextBlock>
                            <ContentPresenter x:Name="contentPresenter" 
                                              Focusable="False" 
                                              HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" 
                                              Margin="{TemplateBinding Padding}" 
                                              RecognizesAccessKey="True" 
                                              SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" 
                                              VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
                        </DockPanel>
                    </Border>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsDefaulted" Value="true">
                            <Setter Property="BorderBrush" 
                                        TargetName="border" 
                                        Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/>
                        </Trigger>
                        <Trigger Property="IsMouseOver" Value="true">
                            <Setter Property="Background" TargetName="border" Value="{StaticResource Button.MouseOver.Background}"/>
                            <Setter Property="BorderBrush" TargetName="border" Value="{StaticResource Button.MouseOver.Border}"/>
                            <Setter Property="Background" TargetName="timerText" Value="{StaticResource Button.MouseOver.Background}"/>
                            <!--<Setter Property="TimerStart" Value="True"></Setter>-->
                        </Trigger>
                        <Trigger Property="IsPressed" Value="true">
                            <Setter Property="Background" TargetName="border" Value="{StaticResource Button.Pressed.Background}"/>
                            <Setter Property="BorderBrush" TargetName="border" Value="{StaticResource Button.Pressed.Border}"/>
                        </Trigger>
                        <Trigger Property="IsEnabled" Value="false">
                            <Setter Property="Background" TargetName="border" Value="{StaticResource Button.Disabled.Background}"/>
                            <Setter Property="BorderBrush" TargetName="border" Value="{StaticResource Button.Disabled.Border}"/>
                            <Setter Property="TextElement.Foreground" TargetName="contentPresenter" Value="{StaticResource Button.Disabled.Foreground}"/>
                        </Trigger>
                        <Trigger Property="TimerStart" Value="True">
                            <Setter Property="TextBlock.Visibility" TargetName="timerText" Value="Visible"></Setter>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
    <!--#endregion-->

</ResourceDictionary>

MainWindow.xaml

<Window x:Class="ControlsTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008" mc:Ignorable="d"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:ControlsTest"
        xmlns:controls="clr-namespace:WPFUserControls.Controls;assembly=WPFUserControls"
        d:DataContext="{d:DesignInstance Type=local:MainWindowViewModel}"
        Title="MainWindow" Height="240" Width="470">

    <Grid>
        <StackPanel>
            <controls:TimerButton 
                Width="150" Height="50"
                TimerSeconds="5" 
                Command="{Binding TestButtonCommand}"
                CommandParameter="Command Parameter">
                <controls:TimerButton.Content>
                    <StackPanel>
                        <TextBlock Text="The timer button"></TextBlock>
                    </StackPanel>
                </controls:TimerButton.Content>
                <controls:TimerButton.Style>
                    <Style>
                        <Style.Triggers>
                            <Trigger Property="controls:TimerButton.IsMouseOver" Value="True">
                                <Setter Property="controls:TimerButton.TimerStart" Value="True"></Setter>
                            </Trigger>
                        </Style.Triggers>
                    </Style>
                </controls:TimerButton.Style>
            </controls:TimerButton>
        </StackPanel>
    </Grid>
</Window>

TimerButton.cs

namespace WPFUserControls.Controls
{
    public class TimerButton : Button, INotifyPropertyChanged
    {
        #region private fields

        private Timer _timer;
        private int _timerSeconds;
        private int _remainingSeconds;

        #endregion

        #region Dependency Properties

        #region TimerSeconds : int - The number of seconds before the command starts automaticall

        /// <summary>Seconds for auto run command</summary>
        public static readonly DependencyProperty TimerSecondsProperty =
            DependencyProperty.Register(
                nameof(TimerSeconds),
                typeof(int),
                typeof(TimerButton),
                new PropertyMetadata(default(int)));

        /// <summary>Seconds for auto run command</summary>
        [Description("The number of seconds before the command starts automaticall")]
        public int TimerSeconds
        {
            get => (int)GetValue(TimerSecondsProperty);
            set => SetValue(TimerSecondsProperty, value);
        }

        #endregion

        #region TimerTextBlockStyle : Style - Timer TextBlockStyle

        /// <summary>Timer TextBlockStyle</summary>
        public static readonly DependencyProperty TimerTextBlockStyleProperty =
            DependencyProperty.Register(
                nameof(TimerTextBlockStyle),
                typeof(Style),
                typeof(TimerButton),
                new PropertyMetadata(default(Style)));

        /// <summary>Timer TextBlockStyle</summary>
        [Description("Timer TextBlockStyle")]
        public Style TimerTextBlockStyle
        {
            get => (Style) GetValue(TimerTextBlockStyleProperty);
            set => SetValue(TimerTextBlockStyleProperty, value);
        }

        #endregion

        #region TimerStart : bool - summary

        /// <summary>summary</summary>
        public static readonly DependencyProperty TimerStartProperty =
            DependencyProperty.Register(
                nameof(TimerStart),
                typeof(bool),
                typeof(TimerButton),
                new PropertyMetadata(default(bool), OnTimerStartPropertyChanged));

        private static void OnTimerStartPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            if (d is TimerButton timerButton)
            {
                timerButton.OnPropertyChanged(e.Property.Name);
            }
        }


        /// <summary>summary</summary>
        [Description("summary")]
        public bool TimerStart
        {
            get => (bool)GetValue(TimerStartProperty);
            set => SetValue(TimerStartProperty, value);
        }

        #endregion
       
        #endregion

        #region Constructors
        static TimerButton() =>
           DefaultStyleKeyProperty.OverrideMetadata(typeof(TimerButton),
               new FrameworkPropertyMetadata(typeof(TimerButton)));
        public TimerButton() => PropertyChanged += OnPropertyChanged;
        #endregion

        #region Private methods
        private void OnPropertyChanged(object sender, PropertyChangedEventArgs e)
        {
            if (!e.PropertyName.Equals(nameof(TimerStart))) return;
            var timerState = false;

            Dispatcher.Invoke(() => timerState = (bool)GetValue(TimerStartProperty));

            if (timerState)
            {
                Dispatcher.Invoke(() => _timerSeconds = (int)GetValue(TimerSecondsProperty));

                _timer = new Timer(1000) { AutoReset = true };
                _timer.Elapsed += Timer_Elapsed;
                _remainingSeconds = _timerSeconds;
                _timer.Start();
            }
            else
            {
                _timer.Dispose();
                Dispatcher.Invoke(() => SetValue(TimerSecondsProperty, _timerSeconds));
            }
        }

        private void Timer_Elapsed(object sender, ElapsedEventArgs e)
        {
            _remainingSeconds--;
            if (_remainingSeconds == 0) RunCommand();
            else
            {
                Dispatcher.Invoke(() => SetValue(TimerSecondsProperty, _remainingSeconds));
            }
        }

        private void RunCommand()
        {
            if (_timer != null)
            {
                _timer.Stop();
                _timer.Dispose();
            }

            Dispatcher.InvokeAsync(() => Command.Execute(CommandParameter));
        } 
        #endregion

        #region INPC
        public event PropertyChangedEventHandler PropertyChanged;

        protected void OnPropertyChanged([CallerMemberName] string propertyName = null)
            => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        #endregion

    }
}

👍