What is the ConnectionString to create a OdbcConnection for an access mdb file

问题

I want to connect from c# to an Access MDB file by using Odbc.

When I try to execute

OdbcConnection con = new OdbcConnection(
    "Driver={Microsoft Access Driver (*.mdb)};DBQ=c:\\temp\\test.mdb;");

I get the following exception:

exc {System.Data.Odbc.OdbcException (0x80131937): ERROR [IM002] [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified
   at System.Data.Odbc.OdbcConnection.HandleError(OdbcHandle hrHandle, RetCode retcode)
   at System.Data.Odbc.OdbcConnectionHandle..ctor(OdbcConnection connection, OdbcConnectionString constr, OdbcEnvironmentHandle environmentHandle)
   at System.Data.Odbc.OdbcConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningObject)
   at System.Data.ProviderBase.DbConnectionFactory.CreateNonPooledConnection(DbConnection owningConnection, DbConnectionPoolGroup poolGroup, DbConnectionOptions userOptions)
   at System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection)
   at System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)
   at System.Data.ProviderBase.DbConnectionInternal.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory)
   at System.Data.Odbc.OdbcConnection.Open()
   :

What's the Problem here? It complains about "Data source name not found and no default driver specified", but I specified a Driver?

I got the connectionstring with help from here http://www.connectionstrings.com/access#net-framework-data-provider-for-odbc

回答1:

Oh, I just found the source of my Problem. I think others might encounter it as well:

I'm writing a .net application which runs in the 32bit .net vm when the OS is a 32bit Windows, and in the 64bit vm when the OS is a 64bit Windows. Using the 2 odbcad32.exe in syswow and system32 (yes both are named odbcad32.exe even though the one in system32 is for 64bit, and yes that's correct as well) I found out I only have the Access MdB Driver installed for odbc32 bit. So when my application runs on a 64bit Windows, .net wants to use the 64bit Version of odbc and doesn't find the Driver.

Ok, so now I need a 64 bit Access Driver, which does not exist according to this enter link description here. Ok the post is old, so maybe there exists one now?

When I force the Plattform in my Project Settings to x86, it works. Of course, this also forces my app to be run in the 32bit .net vm.

回答2:

Use web config setting like example below

<add      name="ODBCDataConnectionString"   connectionString="Driver=ODBCDriver;server=ODBCServer;"   providerName="System.Data.Odbc"   />

回答3:

You can create a udl file, create your connection, and then open the file in notepad to see the connection string. This has helped me out in the past -

http://msdn.microsoft.com/en-us/library/e38h511e%28v=vs.71%29.aspx

Using this, you can create a regular connection like you would in odbc tool and verify that it works.

Hope that helps.

来源：https://stackoverflow.com/questions/14567220/what-is-the-connectionstring-to-create-a-odbcconnection-for-an-access-mdb-file

标签

.net

ms-access

odbc

connection-string