Comments by Cueen (Top 2 by date)

Cueen 8-Jan-16 7:29am View

Bashir gave some nice point, especially the one regarding the OLEDB. This approach is much faster then Excel Interop however you're unable to do the missing columns, header missing, etc. checks with it.
Nevertheless here is another approach that is much much faster then Excel Interop which uses this C# component for excel files. It can directly export an excel's sheet (or a part of it) into a DataTable with C#.

Cueen 8-Jan-16 6:11am View

I presume you're looking to format just a piece of text in some excel's cell with C#, in that case try this:

application.ActiveCell.get_Characters(1,5)

Note that application is an object of Microsoft.Office.Interop.Excel.Application type.
Also in case you're interested you can check out a C# library for excel files, it can enable you to format the individual characters and words within a cell in a more intuitive manner (see here).