com - COM オブジェクトを公開する dll を ildasm/ilasm ラウンドトリップする方法

Question

COM オブジェクト (相互運用) を公開する dll をラウンドトリップしたい。ildasm を使用して、dll をダンプしました。ildasm ダンプで、クラス名のすべての出現箇所の名前を変更しました。DLL スイッチとリソースのインクルードを使用した Ilasm により、新しい dll が作成されました。この新しい dll (Win7) を登録する方法がわかりません。Regasm/Regedit は、強い名前について不平を言っています。他に何を調整する必要がありますか？ありがとうございました。セッペ

Answer 1

A strong name for an assembly explicitly prevents you from doing this. Strong names were designed to detect somebody tampering with the code of an assembly, useful when the assembly is stored in an insecure location like a website. You are definitely tampering with the DLL so you'll break the strong name. Resigning it is required and that requires access to the private key that was used originally.

That said, there are some mitigating factors in the specific case of a [ComVisible] assembly. There isn't any way for an application to verify the strong name since the client of such an assembly is native code that doesn't know beans about strong names. The strong name is only required to allow the assembly to be registered in the GAC. Which in general is a good place for such assemblies since it helps to avoid DLL Hell.

So there are two things you can do to solve this problem:

• Read the regasm.exe message carefully. It probably only displays a warning if you use the /codebase option. "RegAsm : warning RA0000 : Registering an unsigned assembly with /codebase can cause your assembly to interfere with other applications that may be installed on the same computer. The /codebase switch is intended to be used only with signed assemblies. Please give your assembly a strong name and re-register it." Which really means "You are about to commit yourself to DLL Hell". There are various degrees of DLL Hell, the name+location of the DLL is a fairly mild one. The far more important one is that the interfaces and classes get a new [Guid]. Which they'll automatically get since you changed the names, assuming that there is not a [Guid] attribute present in the original code.

• Just sign the assembly with your own key, using sn.exe. Since nobody can actually check the strong name, any is good enough.

And do keep your eye on the ball, the actual name of the [ComVisible] interface and class names is immaterial in COM. Only the [Guid] matters, that's what the COM client uses to find the types back.