Porting 32 bit CLR UDFs on 64 bit Platforms

    Today I tried to port on a 64 bit platform a few of the CLR UDFs created in the previous posts, this time being constrained to use Visual Basic Studio 2010 Express to create and build the assembly on a x86 platform, and install the assembly on a x64 SQL Server box. From the previous troubleshooting experience between the two platforms, I knew that there will be some challenges, fortunately there was nothing complex. Under SSIS 2008 it’s possible to choose the targeted platform, therefore I was expecting to have something similar also in VB Studio 2010 Express, and after a simple review of Project Properties, especially in what concerns the Compile settings, I found nothing relevant. I tried then the standard approach, so I built the solution, copied the .dll on the target server and tried to register the assembly though I got the following error:

Msg 6218: %s ASSEMBLY for assembly '%.*ls' failed because assembly '%.*ls' failed verification. Check if the referenced assemblies are up-to-date and trusted (for external_access or unsafe) to execute in the database. CLR Verifier error messages if any will follow this message%.*ls

    After several attempts to Google for a solution on how to port 32 bit CLR UDFs on 64 bit Platform or on how to configure VB Studio 2010 Express in order to target solutions for 64 bit platforms, I found a similar question (VB Express target x86 Platform) in MSDN,  Johan Stenberg’s answer completed by JohnWein’s hint, led me to the “Issues When Using Microsoft Visual Studio 2005” document, to be more specific to 1.44 section "References to 32-bit COM components may not work in VB and C# Applications running on 64-bit platforms", of importance being the part talking about "Express Editions". In the document is specified how to modify the project and add in the first PropertyGroup section a PlatformTarget tag with the text value x86, therefore what I had to do was to add the respective tag but with the value x64. After doing this change everything worked smoothly. It’s kind of a mystery why Microsoft hasn’t enabled this feature in Express versions, but in the end I can live with it as long there is a workaround for it.