On excel sheet upload read the workbook and populate data to sharepoint list

Question

Requirement in my current project:
In a document library when I upload an excel sheet, a specific workbook has to be read and the contents have to be uploaded to a sharepoint custom list.
The approach followed was create an event receiver and register as a feature. Following is the code for event receiver.
public override void ItemAdded(SPItemEventProperties properties)
            base.ItemAdded(properties);
            var list = getSPList("{150301BF-D0BD-452C-90D7-2D6CD082A247}");          
            SPListItem doc = properties.ListItem;
            doc["Msg"] = "items deleted from req list";
            doc.Update();
            string excelname=doc.File.Name;
            System.Diagnostics.EventLog.WriteEntry("ExcelUpload", "calling read excel");
            string filepath = doc.File.Url.ToString();
            doc["Msg"] = "excel name" + excelname + filepath;
            doc.Update();
            readExcel(excelname,filepath);
        private static SPList getSPList(String SPListGuid)
           // SPSite Site = SPContext.Current.Site;
            SPSite Site = new SPSite("http://omistestsrv:32252/sites/OMD");
            SPWeb web = Site.OpenWeb();
            Guid listid = new Guid(SPListGuid);
            web.AllowUnsafeUpdates = true;
            SPList List = web.Lists[listid];
            return List;
        private void readExcel(string excelname,string filepath)
            try
                SPSecurity.RunWithElevatedPrivileges(delegate()
                    using (SPSite Site = new SPSite("http://omistestsrv:32252/sites/OMD"))
                        SPWeb web = Site.OpenWeb();
                        string workbookpath = web.Url + "/" + filepath;
                        web.AllowUnsafeUpdates = true;
                        var _excelApp = new Microsoft.Office.Interop.Excel.Application();
                        System.Diagnostics.EventLog.WriteEntry("ExcelUpload", "iside read excel");
    //my code breaks or fails when cursor reaches this statement. I am not able to open the excel sheet, there is no    //problem related to the permission. same code snippet works in a console application. but when tried as an
event    //handler in sharepoint it breaks. can anyone help me to resolve the problem
                        workBook = _excelApp.Workbooks.Open(workbookpath, Type.Missing, Type.Missing, Type.Missing, Type.Missing,Type.Missing,
Type.Missing, Type.Missing, Type.Missing,Type.Missing, Type.Missing, Type.Missing, Type.Missing,Type.Missing, Type.Missing);
                        System.Diagnostics.EventLog.WriteEntry("ExcelUpload", "after excel open");
                            int numSheets = workBook.Sheets.Count;
                            // Iterate through the sheets. They are indexed starting at 1.
                            System.Diagnostics.EventLog.WriteEntry("ExcelUpload", numSheets.ToString());
                            for (int sheetNum = 12; sheetNum < 13; sheetNum++)
                                System.Diagnostics.EventLog.WriteEntry("ExcelUpload", "inside first for
loop");
                                Worksheet sheet = (Microsoft.Office.Interop.Excel.Worksheet)workBook.Sheets[sheetNum];
                                Microsoft.Office.Interop.Excel.Range excelRange = sheet.get_Range("A13",
"P89") as Microsoft.Office.Interop.Excel.Range;
                                object[,] valueArray = (object[,])excelRange.get_Value(
                                    Microsoft.Office.Interop.Excel.XlRangeValueDataType.xlRangeValueDefault);
                                var list = getSPList("{150301BF-D0BD-452C-90D7-2D6CD082A247}");
                                for (int L = 1; L <= excelRange.Rows.Count; L++)
                                    string stringVal = valueArray[L, 1] as string;
                                    if ((valueArray[L, 1] != null) && (!string.IsNullOrEmpty(stringVal)))
                                        System.Diagnostics.EventLog.WriteEntry("ExcelUpload",
"inside second for loop");
                                        SPListItemCollection
listItems = list.Items;
                                        SPListItem item = listItems.Add();
                                        item["Product"] = valueArray[L,
1];
                                        item["App"] = valueArray[L,
2];
                                        web.AllowUnsafeUpdates
= true;
                                        item.Update();
                            web.AllowUnsafeUpdates = false;
                            //Or Another Method with valueArray Object like "ProcessObjects(valueArray);"
                            _excelApp.Workbooks.Close();
                //workBook.Close(false, excelname, null);
                //Marshal.ReleaseComObject(workBook);
            catch (Exception e)
                System.Diagnostics.EventLog.WriteEntry("ExcelUpload", e.Message.ToString());
            finally
                System.Diagnostics.EventLog.WriteEntry("ExcelUpload", "finally block");
Is this the only approach to meet this requirement or is there any other way to crack it. sharepoint techies please help me.

Answer 1

as you described the scenario of the event that it should happen when user upload excel to a document library. Event Receiver is your best bet. However if you would have a requirement that users can send excel files any time to a network file location and
you want to pick it, read it and create list items etc. You would write a sharepoint timer job that would run every 10 minute to check for file and if available on the network drive, perform the operation etc. so that users who send excel file does not need
to come to the sharepoint etc. You can see that you have Event Receivcer option or Timer job option OR you would write a console application to trigger the code at a scheduled time on sharepoint server etc. so you are using the event receiver in the correct
scenario.
Moonis Tahir MVP, MCPD, MCSD.net, MCTS BizTalk 2006/SQL 2005/SharePoint Server 2007 (Dev & Config)