I'm experiencing an error when trying to connect to a remote Oracle 10g database from a C# 2008 Express Edition application I'm developing. I'm trying to use a minimalist, non-intrusive approach to the development with a view to ClickOnce deployment to user workstations.
In respect of the above I've investigated the following documents (amongst others..) -
What is the minimal setup required to deploy a .NET application with Oracle client 11?
http://jeremybranham.wordpress.com/2011/04/25/oracle-instant-client-with-odp-net/
http://ora-00001.blogspot.com/2010/01/odpnet-minimal-non-intrusive-install.html
http://splinter.com.au/using-the-new-odpnet-to-access-oracle-from-c
Connect to Oracle with odp.net and the OCI from C#
In view of the error I've experienced I've created a simple test app. consisting of a single (wpf) page with one button. In the click-event of the button I attempt to create a connection to an Oracle database -
private void button1_Click( object sender, RoutedEventArgs e )
{
OracleConnection oraConnect;
// string previously used OK in other projects
string connectionString = "Data Source=" +
"(DESCRIPTION =(ADDRESS_LIST =(ADDRESS = (PROTOCOL = TCP)(HOST = myServer)(PORT = 1521)))" +
"(CONNECT_DATA =(SERVICE_NAME = myOracleDb)))" +
";Password=myPw;User ID=myID;";
using ( oraConnect = new OracleConnection( connectionString ) )
{
try
{
if ( oraConnect.State == ConnectionState.Closed )
{
oraConnect.Open();
MessageBox.Show( "oraConnect is attempting to open.." );
}
else
MessageBox.Show( "oraConnect open to DB: " + oraConnect.ServerVersion.ToString() );
}
catch ( NullReferenceException nullExcept )
{
MessageBox.Show( "Caught error: ." + nullExcept.ToString() );
}
catch ( OracleException dbEx )
{
MessageBox.Show( "OraException - " + dbEx.Message.ToString());
}
catch ( Exception ex )
{
Exception current;
current = ex;
while ( current != null )
{
current = current.InnerException;
}
MessageBox.Show( "Db base exception - " + ex.GetBaseException().ToString() );
}
finally
{
oraConnect.Close();
}
}
}
Following the information in the above articles I've ensured that the following Dll's are in my "bin" folder -
• oci.dll
• ociw32.dll
• orannzsbb10.dll
• oraocci10.dll
• oraociicus.dll
• msvcr71.dll
(the last named in desperation...) and have referenced 'Oracle.DataAccess.dll'.
The error message (at 'catch ( OracleException dbEx )') is -
"Oracle.DataAccess.Client.OracleException was caught
Message=""
StackTrace:
at Oracle.DataAccess.Client.OracleException.HandleErrorHelper(Int32 errCode, OracleConnection conn, IntPtr opsErrCtx, OpoSqlValCtx* pOpoSqlValCtx, Object src, String procedure)
at Oracle.DataAccess.Client.OracleException.HandleError(Int32 errCode, OracleConnection conn, IntPtr opsErrCtx, Object src)
at Oracle.DataAccess.Client.OracleConnection.Open()
at OracleConnectionTest.Window1.button1_Click(Object sender, RoutedEventArgs e) in C:\Documents\Visual Studio 2008\Projects\OracleConnectionTest\OracleConnectionTest\Window1.xaml.cs:line 69
InnerException: "
Line 69 is 'oraConnect.Open();'.
In addition, the following is reported -
"((Oracle.DataAccess.Client.OracleException)($exception)).DataSource' threw an exception of type 'System.NullReferenceException".
I'm assuming from the NullReferenceException within the datasource that the problem lies in one of the dlls' (?) as I 'new' the OracleConnection above before trying to reference it.
In addition, the code execution jumps the 'catch ( NullReferenceException nullExcept )' and goes straight to the OracleException catch.
Sorry for rambling on but hope this makes sense? Any help/advice appreciated!
OK, very late getting back to this for which many apologies!
In the interim, our DB has been upgraded(!) and in changing the dll list to include -
from the '10' versions, still with no success, I edited App.xaml (following an extensive search here and on the web) with the following -
<system.data>
<DbProviderFactories>
<add name="OracleClient Data Provider"
invariant="System.Data.OracleClient"
description=".Net Framework Data Provider for Oracle"
type="System.Data.OracleClient.OracleClientFactory, System.Data.OracleClient, Version=2.0.0.0, Culture=neutral, PublicKeyToken=##################"/>
</DbProviderFactories>
</system.data>
<!-- publicKeyToken obtained using Reflector to investigate dll -->
<runtime>
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
<dependentAssembly>
<assemblyIdentity name="Oracle.DataAccess"
publicKeyToken="##################"
culture="neutral"/>
<bindingRedirect oldVersion="10.2.0.100"
newVersion="2.112.2.0"/>
</dependentAssembly>
</assemblyBinding>
</runtime>
The bindingRedirect did the trick!
The dll's appear to be extremely dependent on compatible version numbers
Wish I could say I really understood how this works but it does and I now have working connections...