C# 發現之旅第十四講：VB.NET 腳本引擎（上）─ 編譯參數設定與 VBCodeProvider 動態編譯

編譯參數與 Imports 設定

• GenerateExecutable = false、GenerateInMemory = true、IncludeDebugInformation = true
• VB 編譯器 /imports 參數指定全域命名空間，格式：/imports:ns1,ns2
• 與原始碼中 Imports 語句不同，命令列參數影響整個編譯單元

動態編譯核心代碼

myAssembly = (Assembly)myAssemblies[strRuntimeSource];
if (myAssembly == null) {
    myCompilerParameters.GenerateExecutable = false;
    myCompilerParameters.GenerateInMemory = true;
    myCompilerParameters.IncludeDebugInformation = true;

    if (myVBCompilerImports.Count > 0) {
        StringBuilder opt = new StringBuilder();
        foreach (string imp in myVBCompilerImports) {
            if (opt.Length > 0) opt.Append(",");
            opt.Append(imp.Trim());
        }
        opt.Insert(0, " /imports:");
        myCompilerParameters.CompilerOptions = opt.ToString();
    }

    if (bolOutputDebug) {
        Debug.WriteLine("Compile VBA.Net script \r\n" + strRuntimeSource);
        foreach (string dll in myCompilerParameters.ReferencedAssemblies)
            Debug.WriteLine("Reference:" + dll);
    }

    VBCodeProvider provider = new VBCodeProvider();
#if DOTNET11
    ICodeCompiler compiler = provider.CreateCompiler();
    CompilerResults result = compiler.CompileAssemblyFromSource(myCompilerParameters, strRuntimeSource);
#else
    CompilerResults result = provider.CompileAssemblyFromSource(myCompilerParameters, strRuntimeSource);
#endif

    StringBuilder output = new StringBuilder();
    foreach (string line in result.Output) output.Append("\r\n" + line);
    strCompilerOutput = output.ToString();

    if (bolOutputDebug && strCompilerOutput.Length > 0)
        Debug.WriteLine("VBAScript Compile result" + strCompilerOutput);

    provider.Dispose();

    if (!result.Errors.HasErrors) myAssembly = result.CompiledAssembly;
    if (myAssembly != null) myAssemblies[strRuntimeSource] = myAssembly;
}

關鍵點

1. 使用靜態 Hashtable myAssemblies 快取編譯結果，相同腳本文字重複編譯直接取用
2. 相容 .NET 1.1 與 2.0+ 兩套編譯 API
3. 編譯錯誤不拋出例外，透過 CompilerResults.Errors 判斷
4. 編譯輸出文字保存於 strCompilerOutput 供診斷