Dennis,
the best way would be to find the last successful instance of the report using following query
SELECT SI_ID, SI_PARENTID, SI_NAME, SI_LAST_SUCCESSFUL_INSTANCE_ID
FROM CI_INFOOBJECTS WHERE SI_ID = ReportID
OR
SELECT SI_ID, SI_PARENTID, SI_NAME, SI_LAST_SUCCESSFUL_INSTANCE_ID
FROM CI_INFOOBJECTS WHERE SI_NAME = ‘Report Name’ AND SI_INSTANCE = 0 AND
SI_KIND = ‘CrystalReport’
export the report to any format and then stream or
use following code to load the latest instance and then stream
enterpriseSession = sessionMgr.Logon("UserName", "Password", "CMSName", "Authentication");
enterpriseService = enterpriseSession.GetService("InfoStore");
infoStore = new InfoStore(enterpriseService);
infoObjects = infoStore.Query("Select SI_LAST_SUCCESSFUL_INSTANCE_ID From CI_INFOOBJECTS Where SI_NAME='" + sampleReportName + "'");
infoObject = infoObjects[1];
int jobID = (int)infoObject.Properties["SI_LAST_SUCCESSFUL_INSTANCE_ID"].Value;
EnterpriseService tempService = enterpriseSession.GetService("", "RASReportFactory");
reportAppFactory = (ReportAppFactory)tempService.Interface;
reportClientDocument = reportAppFactory.OpenDocument(jobID, 0);
CrystalReportViewer1.ReportSource = reportClientDocument;
Hope it helps.
~ Saurabh