你没看懂什么SymbolDocument()
是...
var asm = AppDomain.CurrentDomain.DefineDynamicAssembly(new AssemblyName("foo"), System.Reflection.Emit.AssemblyBuilderAccess.RunAndSave);
var mod = asm.DefineDynamicModule("mymod", true);
var type = mod.DefineType("baz", TypeAttributes.Public);
var method = type.DefineMethod("go", MethodAttributes.Public | MethodAttributes.Static);
Expression fooExpression = Expression.Divide(Expression.Constant(0), Expression.Constant(0));
var parameters = new ParameterExpression[0];
var generator = DebugInfoGenerator.CreatePdbGenerator();
var document = Expression.SymbolDocument(fileName: "MyDebug.txt");
var debugInfo = Expression.DebugInfo(document, 6, 9, 6, 22);
var expressionBlock = Expression.Block(debugInfo, fooExpression);
var lambda = Expression.Lambda(expressionBlock, parameters);
lambda.CompileToMethod(method, generator);
var bakedType = type.CreateType();
Func<int> method2 = (Func<int>)Delegate.CreateDelegate(typeof(Func<int>), bakedType.GetMethod(method.Name));
try
{
int res = method2();
}
catch (Exception e)
{
Console.WriteLine(e.StackTrace);
}
我生成的Expression
类似于return 0/0;
. 我执行它并捕获异常(请注意,我不使用该Invoke
方法,因为该Invoke
方法会将DivisionByZeroException
用作InnerException
)。
我输出的堆栈跟踪类似于:
在 MyDebug.txt 中的 baz.go() 中:ConsoleApplication85.Program.Test() 中的第 6 行
看到MyDebug.txt:row
6了吗?他们是你SymbolDocument
和你的DebugInfo
。
一个更完整的示例,取自Debugging Dynamically Generated Code (Reflection.Emit)。
static void Test()
{
// create a dynamic assembly and module
AssemblyName assemblyName = new AssemblyName("HelloWorld");
AssemblyBuilder assemblyBuilder = AppDomain.CurrentDomain.DefineDynamicAssembly(assemblyName, AssemblyBuilderAccess.RunAndSave);
// Mark generated code as debuggable.
// See https://docs.microsoft.com/en-us/archive/blogs/rmbyers/debuggableattribute-and-dynamic-assemblies for explanation.
Type daType = typeof(DebuggableAttribute);
ConstructorInfo daCtor = daType.GetConstructor(new Type[] { typeof(DebuggableAttribute.DebuggingModes) });
CustomAttributeBuilder daBuilder = new CustomAttributeBuilder(daCtor, new object[] {
DebuggableAttribute.DebuggingModes.DisableOptimizations |
DebuggableAttribute.DebuggingModes.Default });
assemblyBuilder.SetCustomAttribute(daBuilder);
ModuleBuilder module = assemblyBuilder.DefineDynamicModule("HelloWorld.exe", true); // <-- pass 'true' to track debug info.
var doc = Expression.SymbolDocument(@"Source.txt");
// create a new type to hold our Main method
TypeBuilder typeBuilder = module.DefineType("HelloWorldType", TypeAttributes.Public | TypeAttributes.Class);
// create the Main(string[] args) method
MethodBuilder methodbuilder = typeBuilder.DefineMethod("MyMethod", MethodAttributes.HideBySig | MethodAttributes.Static | MethodAttributes.Public, typeof(void), new Type[] { typeof(string[]) });
// Create a local variable of type 'string', and call it 'xyz'
var localXYZ = Expression.Variable(typeof(string), "xyz"); // Provide name for the debugger.
var generator = DebugInfoGenerator.CreatePdbGenerator();
var debugInfo1 = Expression.DebugInfo(doc, 2, 1, 2, 100);
// Emit sequence point before the IL instructions. This is start line, start col, end line, end column,
// Line 2: xyz = "hello";
var assign = Expression.Assign(localXYZ, Expression.Constant("Hello world!"));
// Line 3: Write(xyz);
MethodInfo infoWriteLine = typeof(System.Console).GetMethod("WriteLine", new Type[] { typeof(string) });
var debugInfo2 = Expression.DebugInfo(doc, 3, 1, 3, 100);
var write = Expression.Call(infoWriteLine, localXYZ);
// Line 4: return;
var debugInfo3 = Expression.DebugInfo(doc, 4, 1, 4, 100);
var block = Expression.Block(new ParameterExpression[] { localXYZ }, new Expression[] { debugInfo1, assign, debugInfo2, write, debugInfo3 });
var lambda = Expression.Lambda<Action<string[]>>(block, Expression.Parameter(typeof(string[])));
// bake it
lambda.CompileToMethod(methodbuilder, generator);
Type helloWorldType = typeBuilder.CreateType();
// This now calls the newly generated method. We can step into this and debug our emitted code!!
var dm = (Action<string[]>)Delegate.CreateDelegate(typeof(Action<string[]>), helloWorldType.GetMethod("MyMethod"));
dm(new string[] { null }); // <-- step into this call
}
将其另存为 Source.txt
1| // Test
2| xyz = "hello";
3| Write(xyz);
4| return;
然后在 bp 上放一个断点dm(new string[] { null })
,然后在 bp 上按 F11。它会要求您提供Source.txt
. 请注意,如果您不选择它,则必须删除该.suo
文件才能再次获取该窗口。
注意使用DebuggableAttribute
. 似乎将动态程序集标记为可调试的技巧。