How to truncate or pad a string to a fixed length in c#

Question

Is there a one-liner way of setting a string to a fixed length (in C#), either by truncating it or padding it with spaces (' ').

For example:

string s1 = "abcdef";
string s2 = "abc";

after setting both to length 5, we should have:

"abcde"
"abc  "

Answer 1

All you need is PadRight followed by Substring (providing that source is not null):

string source = ...
int length = 5;

string result = source.PadRight(length).Substring(0, length);

In case source can be null:

string result = source == null 
  ? new string(' ', length) 
  : source.PadRight(length).Substring(0, length);

Answer 2

private string fixedLength(string input, int length){
    if(input.Length > length)
        return input.Substring(0,length);
    else
        return input.PadRight(length, ' ');
}