initialising strings

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Bob - 27 Mar 2006 10:25 GMT

Hi,
In the IDE is there any way to turn off the compiler warning about strings
being used before being initialised.
Given that a string is an immutable object why bother initialising it before
assigning a value to it?
Thanks
Bob

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Nick Hounsome - 27 Mar 2006 11:10 GMT

> Hi,
> In the IDE is there any way to turn off the compiler warning about strings
[quoted text clipped - 4 lines]
> Thanks
> Bob

A string is immutable but a variable of type string is a reference to a
string and can be changed to a completely different (immutable) string:

string a = "immutable 1";
a = "immutable 2"; // OK
a[2] = 'z'; // error - immutable.

What you are thinking of is a "readonly" string.

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Jon Skeet [C# MVP] - 27 Mar 2006 11:23 GMT

> In the IDE is there any way to turn off the compiler warning about strings
> being used before being initialised.
> Given that a string is an immutable object why bother initialising it before
> assigning a value to it?

It sounds like you don't quite understand the error message properly.

Could you post a short but complete program which demonstrates the
problem?

See http://www.pobox.com/~skeet/csharp/complete.html for details of
what I mean by that.

Then we can try to explain the message.

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Bob - 27 Mar 2006 22:02 GMT

Hi Jon,
Good Call. I went back and re-examined the code and there was a path where a
string could have been used with a null value. I shall check the rest.
Thanks
Bob

> > In the IDE is there any way to turn off the compiler warning about strings
> > being used before being initialised.
[quoted text clipped - 10 lines]
>
> Then we can try to explain the message.

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Jon Skeet [C# MVP] - 28 Mar 2006 06:15 GMT

> Good Call. I went back and re-examined the code and there was a path where a
> string could have been used with a null value. I shall check the rest.

Right - the problem isn't that it could have been used with a null
value. The problem is that local variables don't *have* a value
(logically at least) until they've been definitely assigned.

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Jon Skeet - <skeet@pobox.com>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
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initialising strings

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