new line in Text File

Try this:

FileStream filePath = new FileStream("this.txt", FileMode.OpenOrCreate, FileAccess.Write);
StreamWriter sw = new StreamWriter(filePath);

sw.WriteLine("Input: " + dblInput);
sw.WriteLine("Result: " + dblResults);

sw.Close();
filePath.Close();

Or if you you just want insert a newline after one line of text, just put \r\n at the end of the text, like this:

sw.Writeline("Some sort of text\r\n");

On the Windows family of operating systems, you need to use \r\n rather than just \r or \n to insert a new line into a text file. You can also use Environment.NewLine which returns this string value.

However, crausch's second solution should work fine as this is what the StreamWriter.WriteLine() method itself uses. 

How about...

StreamWriter sw = new StreamWriter(“path”);

sw.Write("Hello \n World");

or

sw.WriteLine("Hello");
sw.Write("World");