How to put a string in a newline?

Question

I am working with strings in C#. I have a string like,

StringBuilder sb = new StringBuilder();
sb.AppendLine(ValidatorMethod1());
sb.AppendLine(ValidatorMethod2());

after "sb" is called on ValidatorMethod1(), I call a ValidatorMethod2() as shown, both returns a error message as a string based on a condition. If ValidatorMethod1() and ValidatorMethod2() returns a error msg, then all is fine. But if ValidatorMethod2() fails, then the length of the error message returned from ValidatorMethod2() is "0", but still a line is appended with "sb" and thus a empty error line is appended after ValidatorMethod1()'s error msg.

I tried googling, but links like:

How to insert newline in string literal? did not help me.

So please can anyone give a idea to, "put the returned string in newline if its length is greater than zero" or do nothing?

EDIT:

Hi All, I guess I dint get the proper solution for which I am lookin for. I do not want to append line after each "sb". But if I have a error msg, then, I want to put in NEWLINE.. Can someone give me a different solution which caters to my need?..

What do you mean by "a string _in_ a newline"? That in itself is nonsense. — Grant Thomas, Dec 03 '13 at 11:01
"String in newline" by which I mean, only if ValidatorMethod2() method returns a error msg, it should be put in newline inserted by ValidatorMethod1() else I dont want the new line to come up with BLANK string. — user2771399, Dec 03 '13 at 11:32

David Pilkington · Accepted Answer · 2013-12-03T11:07:46.720

5

You can us String.IsNullOrEmpty to see if the result has a length greater than 0

For example:

string result = ValidatorMethod2();
if (!String.IsNullOrEmpty(result))
   sb.AppendLine(result);

edited Dec 03 '13 at 11:07

answered Dec 03 '13 at 11:01

David Pilkington

13,528
3
41
73

score 2 · Answer 2 · answered Dec 03 '13 at 11:02

Any reason you're not just checking that yourself? This will hardly add any noticeable overhead:

StringBuilder sb = new StringBuilder();

String msg;

msg = ValidatorMethod1();
if (msg.Length > 0)
    sb.AppendLine(msg);

msg = ValidatorMethod2();
if (msg.Length > 0)
    sb.AppendLine(msg);

In fact, there's no faster way. Even if there'd be some built-in functionality provided by Microsoft, it wouldn't do something significantly different.

score 0 · Answer 3 · answered Dec 03 '13 at 11:02

0

You can use this code for each validator:

string error = null;

// repeat for each validator
error = ValidatorMethod1();
if (!String.IsNullOrEmpty(error)) sb.AppendLine(error);

answered Dec 03 '13 at 11:02

Szymon

42,577
16
96
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Dmitry Bychenko · Answer 4 · 2013-12-03T11:16:07.450

You may try doing something like that (calling AppendLine before each non-empty string if sb contains any text):

StringBuilder sb = new StringBuilder();

String message = ValidatorMethod1();

if (!String.IsNullOrEmpty(message))
  sb.Append(message);

message = ValidatorMethod2();

if (!String.IsNullOrEmpty(message)) {
  if (sb.Length > 0)
    sb.AppendLine();

  sb.Append(message);
}

in general case, when you have many validators:

StringBuilder sb = new StringBuilder();

foreach(String result in getValidatorsResults()) {
  if (String.IsNullOrEmpty(result)) 
    continue;

  if (sb.Length > 0)
    sb.AppendLine();

  sb.Append(result);
}

score 0 · Answer 5 · answered Dec 03 '13 at 11:07

0

You can i.e. do:

string sb1 = ValidatorMethod1();
string sb2 = ValidatorMethod2();
if (sb1 != "") sb.AppendLine(sb1);
if (sb2 != "") sb.AppendLine(sb2);

answered Dec 03 '13 at 11:07

Peaceman71

202
3
11

score 0 · Answer 6 · answered Dec 03 '13 at 11:47

In case you are working with a collection of validation methods, you might want to consider something like this:

var validationMethods = new Func<string>[]
{
    () => ValidationMethod1(),
    () => ValidationMethod2(),
    // Add more validtion methods here
};
string error = string.Join(Environment.NewLine, validationMethods.Select(validationMethod => validationMethod()).Where(message=> !string.IsNullOrEmpty(message)));

This solution is easily scaleable if you are need to change the number of validation methods you want to run in a sequence, or when you even want to have a dynamic number of validation methods (then you should use something like List<Func<string>> instead).

How to put a string in a newline?

6 Answers6