Program.cs

using System;
using System.Diagnostics;
using System.IO;
using System.Runtime.InteropServices;
using System.Threading;
using Microsoft.UI.Dispatching;
using Microsoft.UI.Xaml;

namespace FastTransfer;

public static class Program
{
    private const string RuntimeUrl = "https://aka.ms/windowsappsdk/1.8/runtime/win-x64";
    private const string DotNetUrl = "https://dotnet.microsoft.com/download/dotnet/8.0";

    [DllImport("user32.dll", CharSet = CharSet.Unicode)]
    private static extern int MessageBox(IntPtr hWnd, string text, string caption, uint type);

    private const uint MB_OK = 0x00000000;
    private const uint MB_ICONERROR = 0x00000010;
    private const uint MB_ICONWARNING = 0x00000030;
    private const uint MB_ICONINFORMATION = 0x00000040;

    [STAThread]
    private static void Main(string[] args)
    {
        // 运行时检测：检查 Windows App SDK 运行时是否可用
        if (!CheckWindowsAppSdkRuntime())
        {
            ShowMissingRuntimeDialog("Windows App SDK 运行时",
                "FastTransfer 需要 Windows App SDK 1.8 运行时才能运行。\n\n" +
                "请点击「确定」打开下载页面，安装后重新启动程序。",
                RuntimeUrl);
            return;
        }

        // 检查 64 位进程
        if (!Environment.Is64BitProcess)
        {
            ShowMissingRuntimeDialog("系统架构不匹配",
                "FastTransfer 需要 64 位 Windows 系统。",
                DotNetUrl);
            return;
        }

        try
        {
            // PublishSingleFile 需要设置此环境变量以便 Windows App SDK 运行时找到资源
            Environment.SetEnvironmentVariable("MICROSOFT_WINDOWSAPPRUNTIME_BASE_DIRECTORY", AppContext.BaseDirectory);

            WinRT.ComWrappersSupport.InitializeComWrappers();
            Application.Start(_ =>
            {
                var context = new DispatcherQueueSynchronizationContext(DispatcherQueue.GetForCurrentThread());
                SynchronizationContext.SetSynchronizationContext(context);
                new App();
            });
        }
        catch (Exception ex)
        {
            // 应用启动失败，显示错误信息并打开下载页面
            MessageBox(IntPtr.Zero,
                $"FastTransfer 启动失败：{ex.Message}\n\n" +
                $"请确保已安装最新版 Windows App SDK 运行时。\n\n" +
                "点击「确定」打开下载页面。",
                "FastTransfer - 启动错误",
                MB_OK | MB_ICONERROR);

            try { Process.Start(new ProcessStartInfo(RuntimeUrl) { UseShellExecute = true }); }
            catch { }
        }
    }

    /// <summary>检查 Windows App SDK 运行时是否可用。</summary>
    private static bool CheckWindowsAppSdkRuntime()
    {
        try
        {
            // 尝试获取 WinUI 类型，如果能成功说明运行时已加载
            try
            {
                var assembly = typeof(Microsoft.UI.Xaml.Application).Assembly;
                return assembly != null;
            }
            catch
            {
                // WinUI 类型无法加载，继续检查其他方式
            }

            // 检查注册表
            using var key = Microsoft.Win32.Registry.LocalMachine.OpenSubKey(
                @"SOFTWARE\Microsoft\WindowsAppSDK\1.8");
            if (key != null) return true;

            // 检查环境变量
            var wsdk = Environment.GetEnvironmentVariable("WINDOWSAPPSDK_RUNTIME_PATH");
            if (!string.IsNullOrWhiteSpace(wsdk) && Directory.Exists(wsdk))
                return true;

            // 检查常见安装路径
            var programFiles = Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles);
            var runtimeDir = Path.Combine(programFiles, "WindowsApps",
                "Microsoft.WindowsAppRuntime.1.8");
            if (Directory.Exists(runtimeDir))
                return true;

            // 检查输出目录
            var baseDir = AppContext.BaseDirectory;
            if (Directory.Exists(baseDir) &&
                Directory.GetFiles(baseDir, "Microsoft.WindowsAppRuntime*.dll").Length > 0)
                return true;

            return false;
        }
        catch
        {
            // 检测出错时默认允许尝试运行
            return true;
        }
    }

    /// <summary>显示运行时缺失对话框，并提供下载链接。</summary>
    private static void ShowMissingRuntimeDialog(string title, string message, string downloadUrl)
    {
        var result = MessageBox(IntPtr.Zero,
            message + "\n\n点击「确定」打开下载页面。",
            $"FastTransfer - 缺少 {title}",
            MB_OK | MB_ICONWARNING);

        if (result == 1) // IDOK
        {
            try
            {
                Process.Start(new ProcessStartInfo(downloadUrl)
                {
                    UseShellExecute = true,
                    Verb = "open"
                });
            }
            catch
            {
                MessageBox(IntPtr.Zero,
                    $"无法打开浏览器。请手动访问：\n{downloadUrl}",
                    "FastTransfer",
                    MB_OK | MB_ICONINFORMATION);
            }
        }
    }
}