SQL 2012 :: Check Columns Before Process And Calculate Size In Byte In SSIS

I need find out the number of columns in flat file before i process that particular file.

I have file name in @filename variable and file path is @filepath variable.

But do not not that how i will check the column name in before i will process that file.

@filePath = C:DatabaseSourceFilesCAHCVSSourceFiles

And I am using for each loop container to read the file one by one and put the file name in @filename variable.

and my file name like

Product_20120607060930.txt
Product_20130708060930.txt

My file structure is:

ID,Name,City,Country,Phone
1,Riya,Pune,India,454564
2,Jiya,New Jersey,India,454564
3,Riya,St Louis,USA,454564
4,Riya,Belleville,USA,454564
5,Riya,Miami,USA,454564

Now what i have to do is i need to make sure that ID,Name,City,County,Phone is there in flat file. if it is not there then i have to send mail to client saying that file is not valid.

Let me know how i will do it.I need to also calculate the size of flat file.