VB call to MsiLocateComponent function in msi.dll

Question

I am trying to get the installation path of Office programs as this microsoft kb article suggests (since Office start menu shortcuts don't point to paths anymore; thank you Microsoft).

Of course, the KB example uses C++ and native libraries, which I tried to replicate in VB.NET with the following code

<Runtime.InteropServices.DllImport("msi.dll")> Public Shared Function MsiLocateComponent(szComponent As String, ByRef lpPathBuf As Char(), ByRef pcchBuf As Integer)
End Function

I call this function from the following, which I expect to return a message box with at least the dot (if the rest fails). Instead, I get nothing at all, so I assume that the code runs into some sort of error (which is silent though because I get no exception).

Shared Function DealWithWinInstallerPath(ProgramPath As String) As String
    Dim sPath(300) As Char
    Dim sSize As Integer = 300
    Dim state As Integer = MsiLocateComponent("{019C826E-445A-4649-A5B0-0BF08FCC4EEE}", sPath, sSize)
    MsgBox(state & ".")
End Function

(Note that the function has an argument that will be used in the future, but its contents are just for testing purposes).

Am I declaring the function incorrectly? Passing the wrong arguments? Is msi.dll not the right name for the library? The msdn database doesn't help much either.

Answer 1

For managed code, the Microsoft.Deployment.WindowsInstaller interop assembly found in Windows Installer XML's (WiX) Deployment Tools Foundation (DTF) is the way to go. DTF's ComponentInstallation class has a read only property called Path that encapsulates the call to MsiLocateComponent()

Once installed, you can find the DLL in C:\Program Files (x86)\WiX Toolset v3.8\SDK.

You can also read through the source code for pointers on how to P/Invoke MSI API calls.

Answer 2

MsiGetComponentPath is preferred if you read the MSDN docs, and there's an interop example here:

http://www.pinvoke.net/default.aspx/msi.MsiGetComponentPath