This SqlTransaction has completed; it is no longer usable, why?

Question

Code:

I am trying to run this function but it throws error: This SqlTransaction has completed; it is no longer usable.

I have used every other way but not working. I have used it without USING but still same error.

Why?

public Boolean AddWorkProgress(int WorkID, int ContractorID, float PhysicalProgress, 
  decimal FinancialProgress, int UserID, int OrgID, float FinancialProgressPecentage)
{
   SqlCommand SqlCom = new SqlCommand("AddWorkProgress", DataBaseConnection.OpenConnection());
   SqlCom.CommandType = CommandType.StoredProcedure;

   using (SqlTransaction sqlTrans = SqlCom.Connection.BeginTransaction()) 
   {
      SqlCom.Transaction = sqlTrans;

      try
      {
         SqlCom.Parameters.AddWithValue("@Work_ID", WorkID);
         SqlCom.Parameters.AddWithValue("@Contractor_ID", ContractorID);
         SqlCom.Parameters.AddWithValue("@PhysicalProgress", PhysicalProgress);
         SqlCom.Parameters.AddWithValue("@FinancialProgress", FinancialProgress);
         SqlCom.Parameters.AddWithValue("@OrgID", OrgID);
         SqlCom.Parameters.AddWithValue("@fk_WebUsers_UserID", UserID);
         SqlCom.Parameters.AddWithValue("@FinancialProgressPercentage", FinancialProgressPecentage);
         SqlParameter SqlParamReturnStatus = new SqlParameter("@ReturnStatus", SqlDbType.Bit);
         SqlCom.Parameters.Add(SqlParamReturnStatus);
         SqlParamReturnStatus.Direction = ParameterDirection.Output;
         SqlParameter SqlParamReturnStatusMessage = new SqlParameter("@ReturnStatusMessage", SqlDbType.VarChar, -1);
         SqlCom.Parameters.Add(SqlParamReturnStatusMessage);
         SqlParamReturnStatusMessage.Direction = ParameterDirection.Output;
         SqlCom.ExecuteNonQuery();
         DataBaseConnection.CloseConnection();

         string ReturnStatusMessage = Convert.ToString(SqlParamReturnStatusMessage);
         Boolean ReturnStatus = Convert.ToBoolean(SqlParamReturnStatus.Value);
         // ProgressID = Convert.ToInt64(SqlParamReturnProgressID.Value);

         sqlTrans.Commit();
         return ReturnStatus;
      }

      catch (Exception ex)
      {
         sqlTrans.Rollback();
         sqlTrans.Dispose();

         throw ex;
      }
   }
}

Answer 1

You're closing connection before commiting transaction:

DataBaseConnection.CloseConnection();
// skipped code
sqlTrans.Commit();

As from MSDN:

Both Commit and Rollback generates an InvalidOperationException if the connection is terminated or if the transaction has already been rolled back on the server.

This is exactly your case - connection gets closed before commit/rollback of transaction.