all list items are converted into excel through programicall

Hi Koti,
As per my understanding you want to expost Sharepoint list to Excel spreadsheet. Here are the steps:

1. In your SharePoint site, on the top link bar, click Documents and Lists.
2. On the Documents and Lists page, click the list that you want to export to Excel.
3. On the page that displays the list, under Actions, click Export to spreadsheet.
4. In the File Download dialog box, click Open.
5. In the Opening Query dialog box in Excel, click Open.
• If no workbook is open, Excel creates a new blank workbook and inserts the list on a new worksheet.
• If a workbook is open, in the Import Data dialog box, select one of the following options:
• To insert the list in the active worksheet, click Existing worksheet.

In the worksheet, click the cell where you want to place the upper-left corner of the list, and then click OK.

• To insert the data in a new worksheet, click New worksheet and click OK.

• To insert the data in a new workbook, click New workbook and click OK.
• To create a PivotTable report based on the list, click Create a PivotTable report, and follow the steps in the PivotTable and PivotChart Wizard.
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  Original link: http://office.microsoft.com/en-in/excel-help/export-a-sharepoint-list-to-a-spreadsheet-HA001119639.aspx