I've downloaded over a dozen different releases of the x64 ODAC and ODP releases. In every single one, all instances of the supposedly 64-bit oracle.dataaccess.dll identify in Visual Studio as x86. So, when I have a 64-bit project, this results in the design-time warning "There was a mismatch between the processor architecture of the project being built "AMD64"and the processor architecture of the reference "Oracle.DataAccess, Version 18.104.22.168, Culture=neutral, PublicKeyToken=89b483f429c47342, processorArchitecture=x86", "x86"
Is there any way to obtain a version of Oracle.DataAccess.dll that can be used in a 64-bit project?
It's possible that you have a 32-bit ODP.NET version in the GAC, which then shows up in Visual Studio when searching for the assembly. By default, the latest ODAC versions do not GAC ODP.NET. Only the earlier ODAC versions GAC by default. What you may want to do is browse to the directory where 64-bit ODP.NET is installed and add it from the file system, as opposed to the GAC.