save data from every loop in excel

Question

Hi All,

I wanted to export data to excel. 
here is the code that i wrote:

Microsoft.Office.Interop.Excel.Application xla = new Microsoft.Office.Interop.Excel.Application();

            Workbook vb = xla.Workbooks.Add(XlSheetType.xlWorksheet);

            var Worksheet = (Worksheet)xla.Worksheets.Add(Type.Missing, Type.Missing, Type.Missing, Type.Missing);

                 foreach (logic)

            {
                 //logic to get data
                // I put data to excel cells
                example:  Worksheet.Cells[i + 1, 1] = bla bla;
             }

     Worksheet ws = (Worksheet)xla.ActiveSheet;

     ws.SaveAs(@"c:\Documents and Settings\Desktop\output1.xls");

Now my problem is: I dont want to save xls file in last step.

I want to save data in excel file in every loop. It means that If any exception comes at least I have data of the passed loops.

Many thanks,

Darma