AccessViolationException - Connection.Open()

Question

Hey guys, I have a really severe problem not beeing able to persist a suspended Windows Workflow Foundation workflow. (using Oracle.DataAccess 2.111.6.20)
I want to persist such a workflow to the database when it get´s inactive. My problem is in exact that case I am not able to open a OracleConnection to the database. If I open the connection before or after the actual persistence should take place everything works as expected.
The result on con.Open() are just these 2 exceptions:
A first chance exception of type 'System.AccessViolationException' occurred in Oracle.DataAccess.dll
A first chance exception of type 'Oracle.DataAccess.Client.OracleException' occurred in Oracle.DataAccess.dll
The testcode is kind of simple:
private void TestOraConnect()
// Create the connection object
OracleConnection con = new OracleConnection();
con.ConnectionString = "user id=test;password=pass;connection timeout=2147483647;data source=(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=myhost)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=myservice)))";
con.Open();
con.Close();
Thank you for any help, suggestions to overcome this problem.

Answer 1

ODP.NET consists of managed and unmanaged code. Every time a new ODP.NET version is installed, it inserts its bin directory onto the Windows PATH setting. Thus, all existing ODP.NET apps will then use this new installed version.
The problem that can arise is if you do not want all your ODP.NET instances using the same version. To support this scenario, you can specify the directory that each individual ODP.NET app should use to find its unmanaged DLLs via the DllPath setting in the Registry or .NET config file:
DLL search order discussed here:
http://docs.oracle.com/cd/E20434_01/doc/win.112/e23174/InstallODP.htm#sthref94
DllPath setting discussed here:
http://docs.oracle.com/cd/E20434_01/doc/win.112/e23174/featConfig.htm#BABCBFDJ