3 replies to this topic

[vengeanz]

Hi,

I've been trying to use the function MsiQueryProductState or property Installer.ProductState to check if an MSI product is installed.

I checked msi.h to see what constants I would need if I wanted to use the COM object Installer.ProductState in a vbscript and I came across something I thought was strange.

in msi.h they declare

typedef enum tagINSTALLSTATE
{
...
INSTALLSTATE_ADVERTISED = 1
INSTALLSTATE_REMOVED = 1
...
}

If the function returns 1 how do I know if the product is either advertised or removed or am I missing something here?

cheers
vengeanz

[Gareth at Serif]

For situations like this I've simply set a new row in the Upgrade table with a flag for OnlyDetect. This will find your product and set a property accordingly that you can then detect within your package (after AppSearch in your sequence) to see if the other product(s) is present on the system or not.

Regards,
Gareth

[vengeanz]

Hey Gareth,

Thanks for your reply.

In this situation I wanted to check if the product is installed from VBscript or C code, without actually running any specific MSI package.

I think I can do this, but I was wondering why the enum in the msi.h file has two (and I would have thought distinct) install states having the same value.

The way I see it Advertised is a form of Installed Product whereas Removed is ... well, removed.

so if I get a 1 back from either function is my product installed or not?


Cheers
vengeanz

[Zweitze]

The return type INSTALLSTATE is used for multiple functions. In this case, INSTALLSTATE_REMOVED can be returned from MsiGetComponentState, in which case it means that the component is about to be removed. Note that components can never be advertised - only features can.

When a product is not installed, MsiQueryProductState returns INSTALLSTATE_ABSENT. This value is also returned when the product was installed some time ago, but not anymore.

BTW You can also search on products using an upgrade code - look at MsiEnumRelatedProducts.