使用Cecil在函数周围插入begin/end块

AssemblyDefinition assembly = AssemblyDefinition.ReadAssembly("YourAssembly.dll");

TypeDefinition type = assembly.MainModule.GetType("YourNamespace.YourClass");
MethodDefinition method = type.Methods.Single(m => m.Name == "YourMethod");

// 创建begin块
Instruction beginInstruction = Instruction.Create(OpCodes.Nop);
method.Body.Instructions.Insert(0, beginInstruction);

// 创建end块
Instruction endInstruction = Instruction.Create(OpCodes.Nop);
method.Body.Instructions.Add(endInstruction);

foreach (Instruction instruction in method.Body.Instructions)
{
    if (instruction.Operand is Instruction targetInstruction)
    {
        if (targetInstruction == method.Body.Instructions[0])
        {
            // 更新跳转到begin块的指令
            instruction.Operand = beginInstruction;
        }
        else if (targetInstruction == method.Body.Instructions[method.Body.Instructions.Count - 1])
        {
            // 更新跳转到end块的指令
            instruction.Operand = endInstruction;
        }
    }
}

assembly.Write("ModifiedAssembly.dll");