null vs String.Empty

Nemanja Trifunovic

Chris Maunder wrote:

do you prefer to return null or String.Empty?

Neither. If a function "fails", I simply throw an exception.

Dario Solera

I'd say it could be more correct to return String.Empty, but I use null. Actually I don't know what is "phisically" String.Empty, but I guess it's an instance. If you return a null, at least you save memory and therefore less GC calls are needed (especially because you're using strings). IMHO.

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Chris Losinger

C++ doesn't have String.Empty.

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Dario Solera

Nemanja Trifunovic wrote:

Neither. If a function "fails", I simply throw an exception.

It could be correct, if the method actually fails. A null indicates some "void" result, I guess, and not necessarily a failure or error. :)

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Graham Bradshaw

Neither. I would never mix the return value and the success/fail. In MFC/C++, I'd do that as a function that returned a BOOL, indicating whether it worked or not, and a reference to a CString as a parameter.

Judah Gabriel Himango

String.Empty is in the .NET framework

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Nish Nishant

Chris Losinger wrote:

C++ doesn't have String.Empty.

It does if you turn on /clr - and then you have String::Empty :rolleyes:

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Zac Howland

Chris Losinger wrote:

C++ doesn't have String.Empty.

Returning a string("") or CString("") would be almost equivalent to String.Empty.

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Douglas Troy

Not sure it matters, since you can just use the following check:

if (!string.IsNullOrEmpty(MyReturnStringValue)) 
{ 
    ... 
}

But I generally return empty strings ...

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Judah Gabriel Himango

If the function truely failed, that's what exceptions are for. If the function has functioned properly (has not failed) but the there is no result, that's when you return null. Say you had a function like this: public string GetNodeTextAtIndex(int index) { ... } If the function fails for any reason (say, bad input, maybe specifying a negative number as the index), then you throw an exception. If the function otherwise succeeds, but doesn't find any node at that index, you return null.

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Kevin McFarlane

If the method actually fails then throwing an exception is appropriate. But if the method doesn't fail then returning String.Empty or null could be valid depending on the context. However, in general, I like to interpret null as either "not initialised" or indicative of an error. Ideally the source code should describe exactly what it means when it returns an empty string or or a null.

Kevin

Colin Angus Mackay

It depends. It may be valid to return an empty string, in which case you can't use it to signify a failure, in which case null is the best option.

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Anish M

May be null, but for sure not an Empty String

led mike

Chris Maunder wrote:

and that function fails

Based on the responses so far you need to define "fails". IMHO failure indicates an exceptional condition and therefore an exception should be thrown. However if you are referring to a valid outcome of an operation I would likely choose null over an empty string for two reasons: 1) it is more efficient 2) Since the caller must "check" the return value to determine the outcome, it is part of the contract and documented, and therefore is not significant in ways other than efficiency.

led mike

Kevin McFarlane

Good summary, Judah.:)

Kevin

Nemanja Trifunovic

Judah Himango wrote:

String.Empty is in the .NET framework

I know that. I usually don't criticize things I don't know :) [EDIT} So you answered to Chris L. not me. Another CP forum joke[/EDIT]

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Nemanja Trifunovic

Dario Solera wrote:

It could be correct, if the method actually fails.

Chris explicitelly said "fails", whatever he meant by that :)

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Dario Solera

Nemanja Trifunovic wrote:

Chris explicitelly said "fails", whatever he meant by that

Yes, sorry, I noticed it too late... :)

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realJSOP

I return an empty string.

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Andy Brummer

I would definitely never use String.Empty. Using a valid string as an error code is just crazy talk. I would normally throw an exception, unless "failure" is common or profiling warranted removing the exception. Then I would return a flag and make the string a ref or an out parameter. I'm concerned that the question itself might be a lingering symptom of your VBScript hacking days. Just open an old C++ COM app and breathe in the putrid stench of all those HRESULTS and the path ahead should become clear. :-D

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