New Post: How to display excel file without using SaveAS method

First of all i like to appriciate for such a useful functionality.
I like to use it, My requirement is as below..
(1)Working on a wpf c#.net application with mvvm design pattern. Having the requirement to export to excel(independent of excel installation, should be compatible with 32bit and 64 bit both) the nested(master and child) datagrid data.
(2)I also have the requirement to format the header cells and also merge the cells from where child data suppose to start. as following


I think i can achieve all this using closed xml with fast speed, am i right?

I have few doubts.
(1)i am not able to run the examples. While i am trying to run ClosedXML_Examples.exe it throws error of object reference and redirects to debug point "f (opCell.FormulaReference.FirstAddress.Equals(opCell.Address))". Before it, i have corrected the excel file locations as D:\drive does not exist on my machine. Can you help me how can i make it running.
(2)I read somewhere in reviews that it doesn't work properly or gives out of memory exception when no. of record is more then 1000, is this true...any correction made in the latest version?

Please help me with the above so i can start using codeplex and meet my deadlines.