Writing lines to a file using the C# with Example

System.IO.StreamWriter class 
The System.IO.StreamWriter class: 
Implements a TextWriter for writing characters to a stream in a particular encoding. 
Using the WriteLine method, you can write content line-by-line to a file. 
Notice the use of the using keyword which makes sure the StreamWriter object is disposed as soon as it goes out 
of scope and thus the file is closed. 
string[] lines = { "My first string", "My second string", "and even a third string" }; 
using (System.IO.StreamWriter sw = new System.IO.StreamWriter(@"C:\MyFolder\OutputText.txt")) 
{ 
foreach (string line in lines) 
{ 
sw.WriteLine(line); 
} 
} 
Note that the StreamWriter can receive a second bool parameter in it's constructor, allowing to Append to a file 
instead of overwriting the file: 
bool appendExistingFile = true; 
using (System.IO.StreamWriter sw = new System.IO.StreamWriter(@"C:\MyFolder\OutputText.txt", 
appendExistingFile )) 
{ 
sw.WriteLine("This line will be appended to the existing file"); 
}