Export Gridview in excel file

Question

Hi,

I want to export gridview to excel file and import excel to gridvie.

when i open this exported file I am getting the following warning message.

The file format and extension of 'Export.xls'  don't match the file could not be correpted or unsafe. Unless you trust its source, don't open it. Do you want to open it anyway ?

I searched for this warning message but i am not getting correct result.

In Excel file old version(2003) format it is working properly but when I open this file in latest version (after 2007) I am getting warning message and my operations also failed.

so pleas tell me how to export and import gridview in latest version excel file .