Question

I’ve been using some code I’ve found on the net to query the GAC using the fusion.dll however I’ve recently been getting a few error reports back complaining of an OverflowException.

    // If assemblyName is not fully qualified, a random matching may be returned!!!!
    public static String QueryAssemblyInfo(String assemblyName)
    {
        ASSEMBLY_INFO assembyInfo = new ASSEMBLY_INFO();
        assembyInfo.cchBuf = 512;
        assembyInfo.currentAssemblyPath = new String('\0',
        assembyInfo.cchBuf);
        IAssemblyCache assemblyCache = null;
        // Get IAssemblyCache pointer
        IntPtr hr = GacApi.CreateAssemblyCache(out assemblyCache, 0);
        if (hr == IntPtr.Zero)
        {
            hr = assemblyCache.QueryAssemblyInfo(1, assemblyName, ref assembyInfo);
            if (hr != IntPtr.Zero)
                Marshal.ThrowExceptionForHR(hr.ToInt32());
        }
        else
            Marshal.ThrowExceptionForHR(hr.ToInt32());
        return assembyInfo.currentAssemblyPath;
    }

The offending code is when its trying to convert the IntPtr to a Int32 when its actually an Int64, but the problem is the Marshal.ThrowExceptionForHR only accepts an Int32 so I’m a bit stuck for what to do. At the moment I’m just handling the exception but I’d like to know what is the correct way of doing it?

Marlon

Answer 1

Check the signature on your DllImport for CreateAssemblyCache. It looks like it should be int, not IntPtr

[DllImport("fusion.dll")]
internal static extern int CreateAssemblyCache(
    out IAssemblyCache ppAsmCache, int reserved);