Specifies the CLSID of a class that can emulate the current class.

Registry Entry

      TreatAs = {CLSID_TreatAs}


This is a REG_SZ value.

Emulation is the ability of one application to open and edit an object of a different class, while retaining the original format of the object. Resolution occurs on the local computer, so in remote activation case, resolution occurs on the client computer using the CLSID specified by TreatAs.

DCOM looks at the local registry for TreatAs, even if you call the CoCreateInstance function and specify a remote server. This means that if you have a TreatAs entry for Class1 to be treated as Class2 on your local computer, but you call CoCreateInstance to create an instance of Class1 and you specify a remote server, DCOM will try to create an instance of Class2 on the remote server, even if Class2 is not registered on the remote server, which will cause the call to CoCreateInstance to fail.