Need help in Transactionscope

Question

I am using Transactionscope for transaction. In this transaction... I used two databases Oracle and Sql server.


1st - Get data from Sql server
2nd -  Upload sql data on oracle server
3rd - Now update flag on sql server of uploaded data 



above task done on the button click

 var transactionOptions = new TransactionOptions();
                transactionOptions.IsolationLevel = System.Transactions.IsolationLevel.ReadUncommitted;
                transactionOptions.Timeout = TransactionManager.MaximumTimeout;


using (TransactionScope DispTran = new TransactionScope(TransactionScopeOption.Required, transactionOptions))
                {
                    try
                    {
                        objUploadReceive.updateDispatchHDRData();


                        objUploadReceive.updateDispatchDTLData();


                        DispTran.Complete();


                        lblMessage.Text = "Dispatch Data Upload Successfully.";
                        DispTran.Dispose();
                    }
                    catch (TransactionException ex)
                    {
                        common.writeLog(ex.Message, "Interface Updation Dispatch", "Exception");


                        MessageBox.Show("Transaction Exception Occured");
                    }
}


when I clicked on the button to perform task. It will upload data . at the same time when i checked data in oracle it is showing. But when i clicked second or third time on the button . It shows last data. Means it is unable to show  live data . after closing the application the i am able to get data in oracle...

I need a suggestion where is the mistake.