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.Runner/ApiPolicy.cs

@@ -64,7 +64,9 @@ internal static class ApiPolicy
                 if (name.Parent is QualifiedNameSyntax q && q.Left == name) continue;
                 // var 推断出的类型在初始化表达式里已经检查过
                 if (name is IdentifierNameSyntax { IsVar: true }) continue;
-                if (name.Parent is MemberAccessExpressionSyntax m && m.Expression == name && model.GetSymbolInfo(name).Symbol is INamespaceOrTypeSymbol) continue;
+                // 类型名只是用来限定成员（AppDomain.CurrentDomain、System.AppDomain.CurrentDomain）：检查后面的成员就够了
+                ExpressionSyntax qualifier = name.Parent is MemberAccessExpressionSyntax inner && inner.Name == name ? inner : name;
+                if (qualifier.Parent is MemberAccessExpressionSyntax m && m.Expression == qualifier && model.GetSymbolInfo(name).Symbol is INamespaceOrTypeSymbol) continue;
 
                 var symbol = model.GetSymbolInfo(name).Symbol;
                 if (symbol == null) continue;

runtime/Sim.Runner/ClockRewriter.cs

@@ -0,0 +1,69 @@
+using System.Text;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Text;
+
+namespace Sim.Runner;
+
+/// <summary>
+/// 编译前把学生代码里的 DateTime.Now / Today / UtcNow 改写成虚拟时钟 Sim.Host.SimClock（实训台上可以拨时间、调倍速，
+/// 教材项目 7 按 6:45 起床、22:00 熄灯等时刻切换情景模式）。只改写语义上确实是 System.DateTime 这三个属性的地方；
+/// 改写不换行，报错和异常里的行号不变。学生在编辑器里看到的仍是原来的代码。
+/// </summary>
+internal static class ClockRewriter
+{
+    private const string Target = "global::Sim.Host.SimClock";
+
+    public static CSharpCompilation Rewrite(CSharpCompilation compilation)
+    {
+        var result = compilation;
+        foreach (var tree in compilation.SyntaxTrees)
+        {
+            var text = tree.GetText().ToString();
+            if (!text.Contains("Now") && !text.Contains("Today")) continue;
+            var rewriter = new Rewriter(compilation.GetSemanticModel(tree));
+            var root = rewriter.Visit(tree.GetRoot());
+            if (!rewriter.Changed) continue;
+            result = result.ReplaceSyntaxTree(tree,
+                CSharpSyntaxTree.ParseText(SourceText.From(root.ToFullString(), Encoding.UTF8), (CSharpParseOptions)tree.Options, tree.FilePath));
+        }
+        return result;
+    }
+
+    private static string? Replacement(ISymbol? symbol) =>
+        symbol is IPropertySymbol { IsStatic: true, Name: "Now" or "Today" or "UtcNow" } property
+        && property.ContainingType.SpecialType == SpecialType.System_DateTime
+            ? $"{Target}.{property.Name}"
+            : null;
+
+    private sealed class Rewriter(SemanticModel model) : CSharpSyntaxRewriter
+    {
+        public bool Changed { get; private set; }
+
+        public override SyntaxNode? VisitMemberAccessExpression(MemberAccessExpressionSyntax node)
+        {
+            // DateTime.Now、System.DateTime.Now
+            if (Replacement(model.GetSymbolInfo(node).Symbol) is { } replacement)
+            {
+                Changed = true;
+                return SyntaxFactory.ParseExpression(replacement).WithTriviaFrom(node);
+            }
+            return base.VisitMemberAccessExpression(node);
+        }
+
+        public override SyntaxNode? VisitIdentifierName(IdentifierNameSyntax node)
+        {
+            // using static System.DateTime; 之后直接写 Now
+            if (node.Parent is not MemberAccessExpressionSyntax access || access.Expression == node)
+            {
+                if (Replacement(model.GetSymbolInfo(node).Symbol) is { } replacement)
+                {
+                    Changed = true;
+                    return SyntaxFactory.ParseExpression(replacement).WithTriviaFrom(node);
+                }
+            }
+            return base.VisitIdentifierName(node);
+        }
+    }
+}

runtime/Sim.Runner/CompileHints.cs

@@ -17,6 +17,8 @@ internal static class CompileHints
             ("CS0103", "Catch") or ("CS0246", "Catch") => "catch 要小写，括号里写异常类型，例如 catch (Exception ex)。",
             ("CS0246", var name) when name.StartsWith("bool") || name.StartsWith("private") || name.StartsWith("public") || name.StartsWith("string") || name.StartsWith("int") =>
                 $"“{name}”像是类型和名字之间少了一个空格。",
+            ("CS0234", var s) when s.Contains("Properties") => "要用 Properties.Resources，先点代码上方的“项目资源”，添加需要的图片或声音。",
+            ("CS0117", var s) when s.Contains("Resources.") => $"项目资源里还没有“{s[(s.LastIndexOf('.') + 1)..]}”：点代码上方的“项目资源”添加（名字要和代码里一致）。",
             ("CS0103", _) => $"找不到“{source}”。检查拼写和大小写（C# 区分大小写），以及控件的 Name 是否和代码里一致。",
             ("CS1002", _) => "C# 每条语句末尾要有英文分号 ;",
             ("CS1056", _) or ("CS1525", _) when source.Length == 1 && source[0] > 127 => "这里出现了中文标点，C# 代码里的符号要用英文半角。",

runtime/Sim.Runner/StudentCompiler.cs

@@ -56,9 +56,10 @@ internal static class StudentCompiler
 
         using var peStream = new MemoryStream();
         using var pdbStream = new MemoryStream();
-        // 编译改写后的代码（旧版线程 API 换成平台实现），API 检查仍针对学生写的原始代码
-        var emit = LegacyThreadRewriter.Rewrite(compilation).Emit(peStream, pdbStream,
-            options: new EmitOptions(debugInformationFormat: DebugInformationFormat.PortablePdb));
+        // 编译改写后的代码（旧版线程 API 换成平台实现，DateTime.Now 换成虚拟时钟），API 检查仍针对学生写的原始代码
+        var emit = ClockRewriter.Rewrite(LegacyThreadRewriter.Rewrite(compilation)).Emit(peStream, pdbStream,
+            options: new EmitOptions(debugInformationFormat: DebugInformationFormat.PortablePdb),
+            manifestResources: EmptyControlResources(compilation));
         var denied = ApiPolicy.Check(compilation).ToList();
 
         var diagnostics = new JsonArray();
@@ -71,6 +72,39 @@ internal static class StudentCompiler
         return new Result(emit.Success && denied.Count == 0, peStream.ToArray(), pdbStream.ToArray(), diagnostics);
     }
 
+    private static readonly Lazy<byte[]> EmptyResources = new(() =>
+    {
+        var stream = new MemoryStream();
+        using (var writer = new System.Resources.ResourceWriter(stream)) writer.Generate();
+        return stream.ToArray();
+    });
+
+    /// <summary>
+    /// 给学生工程里的每个窗体、控件类嵌一份空的 .resources：VS 生成的 Designer.cs 会用
+    /// ComponentResourceManager(typeof(窗体)).GetObject("…OcxState") 读窗体的 .resx（如 Windows Media Player 控件），
+    /// 平台没有 .resx，有了空资源时取到 null，而不是报"找不到资源"。
+    /// </summary>
+    private static List<ResourceDescription> EmptyControlResources(CSharpCompilation compilation)
+    {
+        var control = compilation.GetTypeByMetadataName("System.Windows.Forms.Control");
+        var resources = new List<ResourceDescription>();
+        if (control == null) return resources;
+        var names = new HashSet<string>();
+        foreach (var tree in compilation.SyntaxTrees)
+        {
+            var model = compilation.GetSemanticModel(tree);
+            foreach (var declaration in tree.GetRoot().DescendantNodes().OfType<Microsoft.CodeAnalysis.CSharp.Syntax.ClassDeclarationSyntax>())
+            {
+                if (model.GetDeclaredSymbol(declaration) is not { } type) continue;
+                var derives = false;
+                for (var t = type.BaseType; t != null && !derives; t = t.BaseType) derives = SymbolEqualityComparer.Default.Equals(t, control);
+                var name = type.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat).Replace("global::", "") + ".resources";
+                if (derives && names.Add(name)) resources.Add(new ResourceDescription(name, () => new MemoryStream(EmptyResources.Value), isPublic: true));
+            }
+        }
+        return resources;
+    }
+
     internal static JsonObject ToJson(Diagnostic diagnostic)
     {
         var span = diagnostic.Location.GetMappedLineSpan();

runtime/Sim.Runner/StudentProgramHost.cs

@@ -104,6 +104,9 @@ internal static class StudentProgramHost
             baseDir = Directory.CreateDirectory(Path.Combine(Path.GetTempPath(), "StudentApp", "bin", "Debug")).FullName;
         }
         baseDir = Path.TrimEndingDirectorySeparator(baseDir) + Path.DirectorySeparatorChar;
+        // 程序目录下的 Resources 文件夹指向素材库：教材用 BaseDirectory + "//Resources//ring.mp3" 播放铃声
+        var resources = Path.Combine(baseDir, "Resources");
+        if (!Path.Exists(resources)) Directory.CreateSymbolicLink(resources, ProjectResources.Directory);
         AppContext.SetData("APP_CONTEXT_BASE_DIRECTORY", baseDir);
         Directory.SetCurrentDirectory(baseDir);
         SimHost.AppBaseDirectory = baseDir;