How to write a string to a text file using c#

Reading and writing files In this chapter, we will look into reading and writing simple files with C.

How to write a string to a text file using c#

More options in demo program; Graphed performance statistics for each method; Added console screenshots for demo program; First off, if you're a developer in a hurry and here for a quick solution i.

That said, the rest of you wise and patient people, read on What follows is an analysis of what should be a dead-simple task: Insert text into an existing file. This all came about because a project of mine required good, byte-at-a-time file handling.

Specifically, given a potentially very large file, I needed to be able to insert, overwrite, find, replace and delete text within that file. Overwriting, truncating and appending are easy, but conflicting opinions abound about how best to insert text into existing files.

The obvious problem is that the BinaryWriter lacks an "insert" mode, so it overwrites anything in its path when you use it. Sure, Microsoft could have cobbled together a special-purpose StreamWriter that transparently handled all the mechanics of this, but they didn't, and it's probably just as well.

Problem Summary For a simple example, say we have a file containing "eggyung". We want to insert "foo" between "egg" and "yung.

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All we need to do is move "yung" over to make room for "foo" in the target file. Some people do this by holding that RH text in some sort of buffer -- a temp file, a MemoryStream, a StringBuilders, maybe just a plain old string.

Others do it by creating a new file and writing to it. First, the original LH segment, then the text being inserted, and finally the original RH segment. After all that, the original file is deleted or moved, and the new file is renamed to take over the original's identity.

I also have an irrational maybe even psychotic aversion to temp files and file-name swapping; maybe I was attacked by a temp file as a child and I've suppressed the memory At any rate, I don't want to write any more data to disk than is necessary, which means not touching the LH segment at all and handling the RH segment as little as possible.

That said, let's dig into the solution Solution Strategy A word about the "without temp files" bit in this article's title In some cases, data can be written to a temporary location that's neither in a temp file, a local variable, nor a MemoryStream.

Where is it then? How about at the end of the target file itself! But the goal here is to accomplish the file modification with a minimum number of bytes written, meaning we buffer only as a last resort. So, after illustrating this simple "target-file-as-its-own-temp-space" trick, I'll describe several other techniques that eliminate the need for any temp buffering at all.

If the text to be inserted is longer than the RH segment, then we know that the RH segment's post-insertion destination does not overlap its original position. This is good; it lets us take a shortcut around buffering: Unfortunately, this doesn't work when the inserted text is shorter than the right-hand segment - at least not if we're copying byte-by-byte as above.How to: Write to a Text File (C# Programming Guide) 07/20/; 2 minutes to read Contributors.

all; In this article. These examples show various ways to write text to a file. Write DataTable as CSV Text File Using C# Find below the code that write data from DataTable as a CSV text file. Using Section. using System; using arteensevilla.comc; using; using; using; Methods for Writing data to CSV.

public static DataTable WriteCSV(String filename, DataTable table) { var. Tour Start here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site. You are working as C# developer, you need to write a program that should read text or csv files from source folder and convert them to an Excel file/s in destination folder.

how to write a string to a text file using c#

Each text or csv file will be converted to separate excel file. If the ReplaceWith text is shorter than the FindWhat text, you can use just steps 3, 4 and 5 from Illustration 3 simply write ReplaceWith starting at the position of FindWhat, then shift the RH segment left & truncate the file. Just a quick look at the way C# writes and reads text files.

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