how to read a text file C#

// To save the text as one string use 'ReadAllText()'
string text = System.IO.File.ReadAllText(@"C:\filepath\file.txt");
// To save each line seperately in an array use 'ReadAllLines()'
string[] lines = System.IO.File.ReadAllLines(@"C:\filepath\file.txt");

using (StreamReader streamReader = new StreamReader(path_name, Encoding.UTF8))
{
  contents = streamReader.ReadToEnd();
}

string[] text = System.IO.File.ReadAllLines(@"C:\users\username\filepath\file.txt");