how to edit specific line of a text file

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hi friends.

i want to edit line 4 of a textfile in my application startup path.

how can i do that.i searched more but there is solutions for replacing words that are in the all line of textfile.

thanks.

Posted 11-Aug-14 6:23am

_Starbug_

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Alternative approach would be: forget those home-baked manipulations and do something cultured, such as XML-based serialization. The best and (by far) simplest way to do that is Data Contract. Please see: http://msdn.microsoft.com/en-us/library/ms733127.aspx[^].

You have nothing to do: the serializer stores you data model (whole object graph, if you will) to an XML file or stream and restore it back to memory when needed. Please see my past answers where I advocate this approach:
Creating property files...[^],
How can I utilize XML File streamwriter and reader in my form application?[^].

—SA

Posted 12-Aug-14 5:37am

Sergey Alexandrovich Kryukov

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Sergey Alexandrovich Kryukov · Accepted Answer · 2014-08-11T06:29:00

Basically, you need to read all the file, modify it and then write it all. This is because you modification can change the length of the line, and it means that all the content below will be rewritten due to the shift. In simplest case, you could use:
http://msdn.microsoft.com/en-us/library/s2tte0y1(v=vs.110).aspx[^],
http://msdn.microsoft.com/en-us/library/bsy4fhsa(v=vs.110).aspx[^],
http://msdn.microsoft.com/en-us/library/92e05ft3(v=vs.110).aspx[^],
http://msdn.microsoft.com/en-us/library/3det53xh(v=vs.110).aspx[^].

If a file is too big, you will have to create a temporary file and read/write line by line, and, at the end, rename temporary file to the name of original one:
http://msdn.microsoft.com/en-us/library/system.io.file.move%28v=vs.110%29.aspx[^].

—SA