dynamic String.Format depending of params

Question

Giving the following examples:

string amountDisplay = presentation.Amount == 1 ? "" : String.Format("{0} x ", presentation.Amount);

is there anyway to use String.Format so it formats depending on properties without having to do a condition of the 'value' of the parameters ?

another use case:

String.Format("({0}) {1}-{2}", countryCode, areaCode, phonenumber);

if I only have phonenumber, I would end up with something like "() -5555555" which is not desirable.

another use case :

String.Format("my {0} has {1} cat[s]", "Aunt", 3)

in this case, I would like to include the s in the [] if the value > 1 for example.

Is there any black 'syntax' of String.Format that removes code parts depending on value of parameters or null ?

Thanks.

Possible duplicate of http://stackoverflow.com/questions/154483/how-to-conditionally-format-a-string-in-net — mickfold, Apr 17 '13 at 19:24
You can do conditionals on numbers that discriminates between positive, negative and zero - http://msdn.microsoft.com/en-us/library/0c899ak8.aspx#SectionSeparator — eulerfx, Apr 17 '13 at 19:29
@eulerfx your comment should be the answer. It's exactly what I was asking here, if there's a way to do it and you prove perfectly. Other solutions are ok but are hacks, yours is what I would call a real answer to the question. Feel free to post it as an answer so I can choose them as the right one. — Bart Calixto, Apr 27 '13 at 23:34

score 2 · Answer 1 · answered Apr 17 '13 at 19:27

Not really. You can hack some things for the plural [s], sure, but it won't be a generic solution to match all your use cases.

You should check the validity of your input regardless. If you're expecting areaCode to be not null, and it's a nullable type like string, do some checks at the start of your method. For example:

public string Foo(string countryCode, string areaCode, string phoneNumber)
{
    if (string.IsNullOrEmpty(countryCode)) throw new ArgumentNullException("countryCode");
    if (string.IsNullOrEmpty(areaCode)) throw new ArgumentNullException("areaCode");
    if (string.IsNullOrEmpty(phoneNumber)) throw new ArgumentNullException("phoneNumber");

    return string.Format(......);
}

It's not the UI's job to compensate for some validation error on the user's input. If the data is wrong or missing, don't continue. It will only cause you strange bugs and lots of pain down the road.

score 1 · Answer 2 · answered Apr 17 '13 at 19:33

You can also try PluralizationServices service. Something like this:

using System.Data.Entity.Design.PluralizationServices;

string str = "my {0} has {1} {3}";
PluralizationService ps = PluralizationService.CreateService(CultureInfo.GetCultureInfo("en-us"));
str = String.Format(str, "Aunt", value, (value > 1) ? ps.Pluralize("cat") : "cat");

score 0 · Answer 3 · answered Apr 17 '13 at 19:23

0

Try using conditional operator:

string str = "my {0} has {1} cat" + ((value > 1) ? "s" : "");

str = String.Format(str, "Aunt", value);

answered Apr 17 '13 at 19:23

Siva Charan

17,940
9
60
95

score 0 · Answer 4 · answered Apr 17 '13 at 19:25

0

Only addresses the second problem, but:

int x = 3;
String.Format("my {0} has {1} cat{2}", "Aunt", x, x > 1 ? "s" : "");

answered Apr 17 '13 at 19:25

sanbornc

766
5
12

dynamic String.Format depending of params

4 Answers4