Upload excel file and display data in GridView in another page using C# in ASP.Net

Hi! I'm new and I got these queries which need some clarity... Query 1 - Grid View: - I have an excel sheet which I import into gridview at runtime. For excel sheet import, I have a fileupload dialog box and an asp.net button control which when clicked imports the sheet contents into a gridview. The problem is I have my fileupload box and button control in a page called Default.aspx and I need the gridview get displayed maximized in a new page called Default2.aspx. Also, I need to specify the row number of the field titles from the excel sheet dynamically at runtime so that the gridview appends any new field/column from that row on. The excel sheets I use contain complex formatting. Is there anyway to display the excelsheet contents as they have been defined and formatted? Query 2 - Sessions:

- I add nodes to my treeview dynamically at runtime. Since HTTP is a stateless protocol, the changes which I do remain only for that session. How do I append the changes I do to the treeview simultaneously in the code?

- I have appended 2 extra columns into the excel sheet generated gridview which take input through dropdownlistbox control at runtime. How do I update and retain those changes in the gridview? Please guide me in this... Thanks...