THEN: Wednesday before Thanksgiving all works well, all my asp.net C# projects can hit/return data from all the Oracle DBs we use.
NOW: Come in Monday: TNS No Listener every time I run any of our apps. It happens right in page_load where the code goes to the DB to fill some screen controls, happens on the first call. All other DB tools on my box work fine, we use Benthic Golden for our DB viewer and it hits all the DBs we use. Ping and TNSPing both return an OK. The Oracle 'Net Manager' config tool tests 'good' on the DB instances.
WHAT I'VE DONE: I installed TortoiseSVN (ver 3.?) as well as Visual SVN for Visual Studio (ver 1.79). I have re-installed Oracle 11.1g client (administrative option). We use 32 and 64 bit installing them in that order, making sure the Environment Variable PATH is correct (it is). This morning I re-installed VS 2012 Ultimate and am still getting the error.
RECENT PC ACTIVITY: Our company just switched over from TFS to Subversion for our code repository. I'm thinking last Wednesday I installed the latest versions (we can use) of Tortoise SVN and Visual SVN. Everyone else on my team has the same, we all stay in lock step with each other, no one else is having this issue.
RESEARCH: 2 days of research mostly has the issue 180 degrees from mine, VS can hit the DB and all other DB tools cannot. The only hit that hit close in my mind was something about how IIS hits the DB. One post said to change the Application Pool advanced settings: change 'Enable 32-bit Applications' to 'True'. That didn't work.
I wanted to at lease throw this out to StackOverFlow before I hand my hard drive over to the tech's for a rebuild and start from scratch.
CURRENT TRY/CATCH INNER EXCEPTION:
System.Exception: ORA-12541: TNS:no listener
SQL Query (TESTDB01): SELECT DISTINCT CUSTOMER_ID AS VALUE, CUSTOMER_NAME AS TEXT FROM CUSTOMERTABLE WHERE CUSTOMER_ID IS NOT NULL
---> System.Data.OracleClient.OracleException: ORA-12541: TNS:no listener
at System.Data.OracleClient.OracleException.Check(OciErrorHandle errorHandle, Int32 rc) at System.Data.OracleClient.OracleInternalConnection.OpenOnLocalTransaction(String userName, String password, String serverName, Boolean integratedSecurity, Boolean unicode, Boolean omitOracleConnectionName) at System.Data.OracleClient.OracleInternalConnection..ctor(OracleConnectionString connectionOptions) at System.Data.OracleClient.OracleConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningObject) at System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnection owningConnection, DbConnectionPool pool, DbConnectionOptions options) at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject) at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject) at System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject) at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection) at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory) at System.Data.OracleClient.OracleConnection.Open() at System.Data.Common.DbDataAdapter.FillInternal(DataSet dataset, DataTable[] datatables, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) at System.Data.Common.DbDataAdapter.Fill(DataSet dataSet, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) at System.Data.Common.DbDataAdapter.Fill(DataSet dataSet) at CsgSystems.DirectNet.Core.CsgSystemsDatabase.GetDataSet(String strSQL, String strInstance)