Set ConnectionString per Thread/CallContext

[Michael Schall]

I need to be able to have a map switch which database server it is
hitting for certain queries.  I have this working however it is not a
per thread/callcontext setting.  It changes it for the map so each
thread will start using a the changed setting.  Is there a workaround
for this?

My code looks like this

--- use ---

        Dim mapper As SqlMapper = DatabaseManager.Instance()
        mapper.DataSource.ConnectionString = connectionString.ConnectionString

        mapper.QueryWithRowDelegate(...)

--- configure --

        Public Sub Configure(ByVal configurationFile As FileInfo)

                Dim builder As DomSqlMapBuilder = New DomSqlMapBuilder()
                _mapper = builder.Configure(configurationFile)

        End Sub

        Friend Function Instance() As SqlMapper
                Dim mapper As SqlMapper
                SyncLock (_lock)
                        mapper = _mapper
                End SyncLock
                Return mapper
        End Function