[2008] Multiple Lines Of Txt File -> Single String?

I have a *.txt file which contains instructions and data, with its own comments (preceded by ! ), blank lines, and each instruction begining on a new line, but occassionally using two lines. Each instruction consists of several feilds seperated by a TAB. Finally each instruction ends in a comma. Only a few different instructions are there (10 different ones) but there are many of each. Spanning a good 2500 lines. Comments and blank lines are obviously of no interest to me. I merely need to read the instructions and the data that follows it.

Now, I have successfully used 'System.IO.StreamReader.ReadLine' to go through it line by line, picking out lines begining with certain strings (first 3 characters of a known instruction). All good, I can 'lift' out the lines of interest and store them, for them to be split up later (seperating their fields into instruction, data, etc..) and then into an array.

The problem is, since some of the data fields in these instructions are so long, it spans two lines, before it ends with a comma. Using the above method, I end up with two array entries for a single instruction, since I have stored individual lines rather than a complete instruction. The only similar situation I can tihnk of to explain this, is to pick out sentences in text, and store each one in a string. Of course these end with a period (full stop) but span two or more lines.

I am hesitant to post an example, since its formatting is rather strange, but it is generated that way from 3rd party software, so I cannot change that for my software application.Perhaps there is no 'graceful' way of doing this, meaning I would have to find a way of 'adding' the second line of the instruction, to the string of the first line. Or perhaps reading each line character by character, literally storing every number/letter until I reach a comma.