项目 7 情景控制：虚拟时钟、项目资源、Windows Media Player、TrackBar

- 虚拟时钟：实训台时钟面板可拨时间、1×/10×/60× 倍速、恢复真实时间；编译时把
  DateTime.Now / Today / UtcNow 改写成 SimClock；评分规则加 clock 步骤
- 项目资源（Properties.Resources）：平台素材库（自绘开关图片、合成门铃声），"项目资源"对话框勾选，
  平台生成 Properties/Resources.Designer.cs；设计器图片框的"图片"属性可选资源；程序目录下的 Resources
  指向素材库；未添加资源时给中文提示
- Windows Media Player（AxWMPLib）：设置 URL 自动播放、Ctlcontrols.play/stop，浏览器里播放声音，
  实训台加广播喇叭；编译时给窗体嵌空资源，OcxState 取到 null 不报错；图片和声音统一按内容缓存（blob）
- TrackBar：拖动、点轨道、方向键，先 ValueChanged 再 Scroll；设计器加"滑动条""媒体播放器"
- 评分规则加 value、media 检查；示例项目 7 任务 1–3（修正书上开关灯判断写反、漏填串口列表）
- 修正：Properties/ 下的资源类不当作窗体；带命名空间的 System.AppDomain.CurrentDomain.BaseDirectory 放行
- 测试：虚拟时钟、TrackBar、项目 7 示例评分、作业起点带资源类

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

runtime/Sim.WinForms/Forms/AxWindowsMediaPlayer.cs

@@ -0,0 +1,166 @@
+using System;
+using System.ComponentModel;
+using System.Drawing;
+using System.IO;
+using System.Security.Cryptography;
+using System.Text.Json.Nodes;
+using System.Windows.Forms;
+using Sim.Host;
+
+namespace System.Windows.Forms
+{
+    /// <summary>
+    /// ActiveX 控件的基类。VS 把 COM 控件拖到窗体上时生成 OcxState = resources.GetObject("…OcxState")，
+    /// 平台编译时给每个窗体嵌了空的资源，这里取到的是 null，不影响使用。
+    /// </summary>
+    public abstract class AxHost : Control, ISupportInitialize
+    {
+        protected AxHost(string clsid) { }
+
+        public State? OcxState { get; set; }
+
+        public void BeginInit() { }
+        public void EndInit() { }
+
+        public class State { }
+    }
+}
+
+namespace WMPLib
+{
+    public enum WMPPlayState
+    {
+        wmppsUndefined = 0, wmppsStopped = 1, wmppsPaused = 2, wmppsPlaying = 3, wmppsScanForward = 4, wmppsScanReverse = 5,
+        wmppsBuffering = 6, wmppsWaiting = 7, wmppsMediaEnded = 8, wmppsTransitioning = 9, wmppsReady = 10, wmppsReconnecting = 11,
+    }
+
+    /// <summary>播放控制：axWindowsMediaPlayer1.Ctlcontrols.play()</summary>
+    public interface IWMPControls
+    {
+        void play();
+        void pause();
+        void stop();
+        double currentPosition { get; set; }
+    }
+
+    /// <summary>播放设置：axWindowsMediaPlayer1.settings.volume</summary>
+    public interface IWMPSettings
+    {
+        bool autoStart { get; set; }
+        int volume { get; set; }
+        bool mute { get; set; }
+        void setMode(string bstrMode, bool varfMode);
+    }
+}
+
+namespace AxWMPLib
+{
+    using WMPLib;
+
+    /// <summary>
+    /// Windows Media Player 控件（教材项目 7 的"广播"播放 ring.mp3）。和真的一样：设置 URL 后自动开始播放（settings.autoStart），
+    /// 也可以调用 Ctlcontrols.play()。声音在浏览器里播放；实训台上的广播喇叭随之亮起。只支持本机文件。
+    /// </summary>
+    [ClientType("AxWindowsMediaPlayer")]
+    public class AxWindowsMediaPlayer : AxHost
+    {
+        private string _url = "";
+        private WMPPlayState _playState = WMPPlayState.wmppsUndefined;
+
+        public AxWindowsMediaPlayer() : base("6bf52a52-394a-11d3-b153-00c04f79faa6")
+        {
+            Ctlcontrols = new Controls(this);
+            settings = new Settings();
+        }
+
+        protected override Size DefaultSize => new(245, 240);
+
+        public string URL
+        {
+            get => _url;
+            set
+            {
+                _url = value ?? "";
+                if (settings.autoStart && _url.Length > 0) Play();
+            }
+        }
+
+        public IWMPControls Ctlcontrols { get; }
+
+        // 属性名和 COM 接口一样是小写
+        public IWMPSettings settings { get; }
+
+        public WMPPlayState playState => _playState;
+
+        public string uiMode { get; set; } = "full";
+        public bool stretchToFit { get; set; }
+        public bool enableContextMenu { get; set; } = true;
+        public string status => _playState == WMPPlayState.wmppsPlaying ? "正在播放" : "已停止";
+
+        public event EventHandler? PlayStateChange;
+
+        private void Play()
+        {
+            LegacyThreads.CheckPoint();
+            // 教材写 BaseDirectory + "//Resources//ring.mp3"：路径里多余的斜杠在 Linux 上也能用
+            var path = _url.StartsWith("file:///", StringComparison.OrdinalIgnoreCase) ? new Uri(_url).LocalPath : _url;
+            if (!File.Exists(path))
+            {
+                SimHost.SendConsole($"Windows Media Player：找不到要播放的文件 {_url}\n");
+                SetState(WMPPlayState.wmppsStopped);
+                return;
+            }
+            var data = File.ReadAllBytes(path);
+            var mime = Path.GetExtension(path).ToLowerInvariant() switch
+            {
+                ".wav" => "audio/wav",
+                ".ogg" => "audio/ogg",
+                ".m4a" or ".aac" => "audio/aac",
+                _ => "audio/mpeg",
+            };
+            var key = SimHost.DataKey(Convert.ToHexString(SHA1.HashData(data)).ToLowerInvariant(), data, mime);
+            SimHost.Send(new JsonObject { ["type"] = "media", ["id"] = SimId, ["action"] = "play", ["key"] = key, ["name"] = Path.GetFileName(path) });
+            SetState(WMPPlayState.wmppsPlaying);
+        }
+
+        private void Stop()
+        {
+            if (_playState != WMPPlayState.wmppsPlaying) return;
+            SimHost.Send(new JsonObject { ["type"] = "media", ["id"] = SimId, ["action"] = "stop" });
+            SetState(WMPPlayState.wmppsStopped);
+        }
+
+        private void SetState(WMPPlayState state)
+        {
+            if (_playState == state) return;
+            _playState = state;
+            PlayStateChange?.Invoke(this, EventArgs.Empty);
+        }
+
+        protected override void WriteProps(JsonObject props)
+        {
+            base.WriteProps(props);
+            props["URL"] = _url;
+        }
+
+        private sealed class Controls(AxWindowsMediaPlayer owner) : IWMPControls
+        {
+            public void play()
+            {
+                if (owner._playState != WMPPlayState.wmppsPlaying && owner._url.Length > 0) owner.Play();
+            }
+
+            public void pause() => owner.Stop();
+            public void stop() => owner.Stop();
+            public double currentPosition { get; set; }
+        }
+
+        private sealed class Settings : IWMPSettings
+        {
+            public bool autoStart { get; set; } = true;
+            public int volume { get; set; } = 50;
+            public bool mute { get; set; }
+            public void setMode(string bstrMode, bool varfMode) { }
+        }
+    }
+}