input == null ? "" : input

[Jeff]

Hey

I've bought the book "ASP.NET 2.0 website programming, Problem, Design,
Solution" and some of its code examples is this code:

protected static string ConvertNullToEm ptyString(strin g input)
{
return (input == null ? "" : input);
}

I have problem understanding this line: (input == null? "":input);
input shall only be set to "" if the value of input is NULL, but I don't see
any if-statement in this code. ?

Best Regards!

Jeff

[Eliyahu Goldin]

? : is a conditional statement. It is a standard statement in all C-based
languages.

--
Eliyahu Goldin,
Software Developer & Consultant
Microsoft MVP [ASP.NET]
"Jeff" <it************ @hotmail.com.NO SPAMwrote in message
news:ew******** ********@TK2MSF TNGP02.phx.gbl. ..

Hey

I've bought the book "ASP.NET 2.0 website programming, Problem, Design,
Solution" and some of its code examples is this code:

protected static string ConvertNullToEm ptyString(strin g input)
{
return (input == null ? "" : input);
}

I have problem understanding this line: (input == null? "":input);
input shall only be set to "" if the value of input is NULL, but I don't
see any if-statement in this code. ?

Best Regards!

Jeff

[Laurent Bugnion]

Hi,

Jeff wrote:

Hey

I've bought the book "ASP.NET 2.0 website programming, Problem, Design,
Solution" and some of its code examples is this code:

protected static string ConvertNullToEm ptyString(strin g input)
{
return (input == null ? "" : input);
}

I have problem understanding this line: (input == null? "":input);
input shall only be set to "" if the value of input is NULL, but I don't see
any if-statement in this code. ?

Best Regards!

Jeff

The '?' conditional statement evaluates the first term (after the '?'
and before the ':') if the condition is true, and evaluates the second
term (after the ':') if the condition is false.

In that case, the code ensures that the "null" value is never returned,
but only an empty string. Translated to an "if" expression, it would be:

if ( input == null )
{
return "";
}
else
{
return input;
}

HTH,
Laurent
--
Laurent Bugnion, GalaSoft
Software engineering: http://www.galasoft-LB.ch
PhotoAlbum: http://www.galasoft-LB.ch/pictures
Support children in Calcutta: http://www.calcutta-espoir.ch