DefaultValueAttribute usage

10 Sep 2006 11:22 PM

Edward Diener

I have a number of questions regarding the DefaultValueAttribute which
is not explained in the rather terse MSDN documentation for it:

1) Should I use it for all properties, even when the property is
initialized to its equivalent 0 value and I do not specifically
initialized in the constructor of my component in which the property
resides ?

2) Is the default value always a constant expression ?

3) Is it used for reference types ? How ? A reference type is not a
constant value.

4) Can it be used for enumerated types ? How ? Is the constructor taking
an Object applied when used for an enumerated type ?

5) Can it be used for the string type, which is a reference type,
passing it a string constant ?

11 Sep 2006 5:34 AM

Mattias Sjögren

Edward,

>1) Should I use it for all properties, even when the property is
>initialized to its equivalent 0 value and I do not specifically
>initialized in the constructor of my component in which the property
>resides ?

Yes

>2) Is the default value always a constant expression ?

Well it has to be if you want to use the DefaultvalueAttribute.

>3) Is it used for reference types ? How ? A reference type is not a
>constant value.

string is a reference type, so yes.

>4) Can it be used for enumerated types ? How ? Is the constructor taking
>an Object applied when used for an enumerated type ?

I believe so.

>5) Can it be used for the string type, which is a reference type,
>passing it a string constant ?

See 3.

Mattias

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Mattias Sjögren [C# MVP] mattias @ mvps.org
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