添加项目文件。

Microsoft Visual Studio Solution File, Format Version 12.00

# 17

VisualStudioVersion = 17.11.35327.3

MinimumVisualStudioVersion = 10.0.40219.1

Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "CountDownList", "CountDownList\CountDownList.csproj", "{C75F6118-1E30-44E0-BE04-A5B4892A418F}"

EndProject

Global

	GlobalSection(SolutionConfigurationPlatforms) = preSolution

		Debug|Any CPU = Debug|Any CPU

		Release|Any CPU = Release|Any CPU

	EndGlobalSection

	GlobalSection(ProjectConfigurationPlatforms) = postSolution

		{C75F6118-1E30-44E0-BE04-A5B4892A418F}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

		{C75F6118-1E30-44E0-BE04-A5B4892A418F}.Debug|Any CPU.Build.0 = Debug|Any CPU

		{C75F6118-1E30-44E0-BE04-A5B4892A418F}.Release|Any CPU.ActiveCfg = Release|Any CPU

		{C75F6118-1E30-44E0-BE04-A5B4892A418F}.Release|Any CPU.Build.0 = Release|Any CPU

	EndGlobalSection

	GlobalSection(SolutionProperties) = preSolution

		HideSolutionNode = FALSE

	EndGlobalSection

	GlobalSection(ExtensibilityGlobals) = postSolution

		SolutionGuid = {C6368404-CD41-46CD-960C-9673EAAAE8D0}

	EndGlobalSection

EndGlobal

<Application x:Class="CountDownList.App"

             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

             xmlns:local="clr-namespace:CountDownList"

             StartupUri="MainWindow.xaml">

    <Application.Resources>

        <ResourceDictionary>

            <ResourceDictionary.MergedDictionaries>

                <ResourceDictionary Source="pack://application:,,,/HandyControl;component/Themes/SkinDefault.xaml"/>

                <ResourceDictionary Source="pack://application:,,,/HandyControl;component/Themes/Theme.xaml"/>

            </ResourceDictionary.MergedDictionaries>

        </ResourceDictionary>

    </Application.Resources>

</Application>

using System.Configuration;

using System.Data;

using System.Windows;

namespace CountDownList

{

    /// <summary>

    /// Interaction logic for App.xaml

    /// </summary>

    public partial class App : Application

    {

    }

}

using System.Windows;

[assembly: ThemeInfo(

    ResourceDictionaryLocation.None,            //where theme specific resource dictionaries are located

                                                //(used if a resource is not found in the page,

                                                // or application resource dictionaries)

    ResourceDictionaryLocation.SourceAssembly   //where the generic resource dictionary is located

                                                //(used if a resource is not found in the page,

                                                // app, or any theme specific resource dictionaries)

)]

namespace CountDownList.Class

{

    public class CountDownBackground

    {

        public CountDownBackground() { }

    }

}