Excel.ApplicationClass excel = new Excel.ApplicationClass();

			excel.Application.Workbooks.Add(true); 
			System.Data.DataTable table = ds.Tables[0];
			int ColumnIndex=0; 
			foreach(DataColumn col in table.Columns)
			{   
				ColumnIndex++;
				excel.Cells[1,ColumnIndex]=col.ColumnName;
			} 
			int rowIndex=0; 
			foreach(DataRow row in table.Rows) 
			{         
				rowIndex++;       
				ColumnIndex=0;         
				foreach(DataColumn col in table.Columns)         
				{  
					ColumnIndex++;                
					excel.Cells[rowIndex+1,ColumnIndex]=row[col.ColumnName].ToString();         
				}