NGWS SDK Documentation -> NGWS SDK Developer Specifications -> Using COM+

1.0 Services from Managed Code Whitepaper



As for transactions in VB7:



Here is a VB7 code sample. 



imports System

imports Microsoft.ComServices

imports System.Runtime.InteropServices

imports ADODB

imports ACCOUNTCom

imports Microsoft.VisualBasic



option strict off



namespace VB7Bank

	public class <ComEmulateAttribute("VB7Bank.AccountInternal"), _

	

GuidAttribute("869DD7AE-62B6-45ed-B999-0702A7702B28"), _

	

TransactionAttribute(TransactionOption.Required)> _

				  Account

	end class



	public class <ComVisible(false)> AccountInternal

		implements IAccount



		private const strConnect = "FILEDSN=BankSample"





		public  function Post(ByVal lngAccountNo As Integer, ByVal

lngAmount As Integer) As String Implements IAccount.Post



			dim strResult as String

			dim adoRS as ADODB._RecordSet

			dim adoConn as ADODB.__Connection

			dim	bSuccess as boolean

			bSuccess = false



			try



				' check for security

				if (lngAmount > 500 or lngAmount < -500)

then

					if not

ContextUtil.IsCallerInRole("Managers") then

						throw new Exception("Need

'Managers' role for amounts over $500")

					end if

				end if



				dim varRows As Object

				dim strSQL As String

				varRows = new Object()

				adoConn = new __Connection()

				adoConn.Open(strConnect)



		TryAgain:

				try

				    strSQL = "UPDATE Account SET Balance 

Balance + " & lngAmount & _

					         " WHERE AccountNo = " &

lngAccountNo

					adoConn.Execute( strSQL, varRows,

128)



				catch e as exception

					dim ct As ICreateTable

					ct = new CreateTable

					ct.CreateAccount()

					goto TryAgain



				end try



				' get resulting balance which may have been

further updated via triggers

				strSQL = "SELECT Balance FROM Account WHERE

AccountNo = " & lngAccountNo

				adoRS = adoConn.Execute( strSQL, varRows,

-1)





				dim intBalance as integer

				intBalance 

cint(adoRS.Fields("Balance").Value)



				' check if account is overdrawn

				if (intBalance) < 0 then

					throw new Exception("Error. Account

" + Str$(lngAccountNo) + " would be overdrawn by " + Str$(intBalance) + ".

Balance is still " + Str$(intBalance - lngAmount) + ".")

				else

					if lngAmount < 0 then

						strResult = strResult &

"Debit from account " & lngAccountNo & ", "

					else

						strResult = strResult &

"Credit to account " & lngAccountNo & ", "

					end if

					strResult = strResult + "balance is

$" + intBalance.ToString() + " (VB7)"

				end if

				bSuccess = true



			finally

				   

				if bSuccess then

					ContextUtil.SetComplete()

					post = strResult

				else

					ContextUtil.SetAbort()

					post = "Failed"

				end if

			end try



		end function



	end class



end namespace