Redirect .NET StreamWriter output to a String variable

Question

I'd like to know if it is possible to redirect StreamWriter output to a variable

Something like

String^ myString;
StreamWriter sw = gcnew StreamWriter([somehow specify myString])
sw->WriteLine("Foo");

then myString will contain Foo. The reason I would like to do this is to reuse a complex function. I should probably refactor it into a String returning function but it still would be a nice hack to know

Answer 1

StreamWriter and StringWriter both extend TextWriter, perhaps you could refactor your method that uses StreamWriter to use TextWriter instead so it could write to either a stream or a string?

Answer 2

You can do this with a StringWriter writing the value directly to a string builder object

StringBuilder sb = new StringBuilder();
StringWriter sw = new StringWriter(sb);
// now, the StringWriter instance 'sw' will write to 'sb'

Answer 3

Try out this code =]

StringBuilder sb = new StringBuilder();
StringWriter sw = new StringWriter(sb);
string s = sb.ToString(); <-- Now it will be a string.

Answer 4

You should be able to do what you need using a Memory Stream.

MemoryStream mem = new MemoryStream(); 
StreamWriter sw = new StreamWriter(mem);
sw.WriteLine("Foo"); 
// then later you should be able to get your string.
// this is in c# but I am certain you can do something of the sort in C++
String result = System.Text.Encoding.UTF8.GetString(mem.ToArray(), 0, (int) mem.Length);

Answer 5

Refactor the method to return string as you mentioned you could. Hacking it the way you are attempting, while academically interesting, will muddy the code and make it very hard to maintain for anyone that follows you.