Thanks for checking. I have added Microsoft.Office.Interop.Excel reference

ArrayList al = new ArrayList();

//Get Sheets collection representing all the worksheets

//in the workbook excelWkBook

Sheets excelSheets = excelWkBook.Worksheets;

//Create null Worksheet object excelWorksheet

Worksheet excelWorksheet = null;

//If the Sheets collection is not empty for the input Workbook, iterate

//through the sheets, get each sheet, and add the name of the sheet

//to the arraylist al

if (excelSheets!= null)

{

for (int i = 1; i<= excelSheets.Count; i++)

{

excelWorksheet = (Worksheet)excelSheets.get_Item((object)i);

al.Add(excelWorksheet.Name.ToString());

}

}