Redirect Console.WriteLine() output to string

Question

I need to take Console.WriteLine() output, and append to a string. I cannot change the Main method to simply append to a string instead of writing to console - I need a method to read all written lines from the console and append them to a string.

Currently, I have been using a FileStream and redirecting console output into a text file, and then reading from that.

var fs = new FileStream("dataOut.txt", FileMode.Create);
var sw = new StreamWriter(fs);
Console.SetOut(sw);
Console.SetError(sw);

And then Console.WriteLine("whatever") writes to the text file. However, I would like to do this without going back and forth from a text file.

Is something like this possible? I realize that the example below does not.

string outString = "";
Console.SetOut(outString);
Console.SetError(outString);

*"I cannot change the Main method to simply append to a string instead of writing to console"* Why not? — 15ee8f99-57ff-4f92-890c-b56153, Aug 09 '16 at 15:18
why don't you store the information in a `StringBuilder Object` then when you are done write the information to a text file that way — MethodMan, Aug 09 '16 at 15:18
@EdPlunkett because I didn't write the code, and do not have the permission to modify it. — lrey, Aug 09 '16 at 15:20
[this post](http://stackoverflow.com/questions/186822/capturing-console-output-from-a-net-application-c) might help — Mong Zhu, Aug 09 '16 at 15:22
@Irey I hope you're taking a break from this nonsense now and then to look at job ads. — 15ee8f99-57ff-4f92-890c-b56153, Aug 09 '16 at 15:22
@15ee8f99-57ff-4f92-890c-b56153: you certainly never use Console.WriteLine() but have written your code in a way that Main() returns a StringBuffer instead ... ? — Thomas Weller, Nov 15 '21 at 13:02

score 16 · Accepted Answer · edited Aug 24 '20 at 14:14

16

Use a StringWriter:

var sw = new StringWriter();
Console.SetOut(sw);
Console.SetError(sw);
Console.WriteLine("Hello world.");
string result = sw.ToString();

edited Aug 24 '20 at 14:14

Patrick Szalapski

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answered Aug 09 '16 at 16:06

Kyle

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Redirect Console.WriteLine() output to string

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