Hello Group,

I posted this in microsoft.public.dotnet.general about a week ago but
haven't had any replies....

The Visual Studio 2005 help for
ConfigurationPropertyAttribute.DefaultValue
provides the following sample:

/////////////////////////////////////////////////
[ConfigurationProperty("maxIdleTime",
DefaultValue = "0:10:0",
IsRequired = false)]
[TimeSpanValidator(MinValueString = "0:0:30",
MaxValueString = "5:00:0",
ExcludeRange = false)]
public TimeSpan MaxIdleTime
{
get
{
return (TimeSpan)this["maxIdleTime"];
}
set
{
this["maxIdleTime"] = value;
}
}

/////////////////////////////////////////////////

What I am wondering is how does the DefaultValue parameter from the
sample code work, i.e.:

>> DefaultValue = "0:10:0",

TimeSpan does not have a constructor or "=" operator that takes a
string parameter, and TimeSpan does not implement IConvertible. For
example, the following does not complile:

>> TimeSpan ts = "0:10:0";

TimeSpan does have a Parse() method that takes a string parameter,
i.e.

>> public static TimeSpan Parse(string s);

but I do not see how it is associated in the above sample code.

So again how does this code from the sample work in regards to
assigning a string
DefaultValue to a TimeSpan value? i.e.:

>> DefaultValue = "0:10:0",

My guess is TimeSpan.Parse() is somehow being called, but where?

TIA,
Keller Beyer
(E-Mail Removed)

On Apr 26, 9:43*pm, Keller <beyer...@aol.com> wrote:
> I posted this in microsoft.public.dotnet.general about a week ago but
> haven't had any replies....
>
> The Visual Studio 2005 help for
> ConfigurationPropertyAttribute.DefaultValue
> provides the following sample:
>
> /////////////////////////////////////////////////
> [ConfigurationProperty("maxIdleTime",
> * * DefaultValue = "0:10:0",
> * * IsRequired = false)]
> [TimeSpanValidator(MinValueString = "0:0:30",
> * * MaxValueString = "5:00:0",
> * * ExcludeRange = false)]
> public TimeSpan MaxIdleTime
> {
> * * get
> * * {
> * * * * return (TimeSpan)this["maxIdleTime"];
> * * }
> * * set
> * * {
> * * * * this["maxIdleTime"] = value;
> * * }
>
> }
>
> /////////////////////////////////////////////////
>
> What I am wondering is how does the DefaultValue parameter from the
> sample code work, i.e.:
>
> >> * DefaultValue = "0:10:0",
>
> TimeSpan does not have a constructor or "=" operator that takes a
> string parameter, and TimeSpan does not implement IConvertible. *For
> example, the following does not complile:
>
> >> * TimeSpan ts = "0:10:0";
>
> TimeSpan does have a Parse() method that takes a string parameter,
> i.e.
>
> >> public static TimeSpan Parse(string s);
>
> but I do not see how it is associated in the above sample code.
>
> So again how does this code from the sample work in regards to
> assigning a string
> DefaultValue to a TimeSpan value? i.e.:
>
> >> * DefaultValue = "0:10:0",
>
> My guess is TimeSpan.Parse() is somehow being called, but where?

I am not familiar with this attribute in particular, but the general
way to do this sort of thing in .NET libraries is to use a type
converter. TimeSpan has an associated TimeSpanConverter, which
converts to/from string. It can be obtained using
TimeConverter.GetConverter(typeof(TimeSpan)), which is probably what
happens here.

On Apr 27, 2:00*am, Pavel Minaev <int...@gmail.com> wrote:
> On Apr 26, 9:43*pm, Keller <beyer...@aol.com> wrote:
>
>
>
>
>
> > I posted this in microsoft.public.dotnet.general about a week ago but
> > haven't had any replies....
>
> > The Visual Studio 2005 help for
> > ConfigurationPropertyAttribute.DefaultValue
> > provides the following sample:
>
> > /////////////////////////////////////////////////
> > [ConfigurationProperty("maxIdleTime",
> > * * DefaultValue = "0:10:0",
> > * * IsRequired = false)]
> > [TimeSpanValidator(MinValueString = "0:0:30",
> > * * MaxValueString = "5:00:0",
> > * * ExcludeRange = false)]
> > public TimeSpan MaxIdleTime
> > {
> > * * get
> > * * {
> > * * * * return (TimeSpan)this["maxIdleTime"];
> > * * }
> > * * set
> > * * {
> > * * * * this["maxIdleTime"] = value;
> > * * }
>
> > }
>
> > /////////////////////////////////////////////////
>
> > What I am wondering is how does the DefaultValue parameter from the
> > sample code work, i.e.:
>
> > >> * DefaultValue = "0:10:0",
>
> > TimeSpan does not have a constructor or "=" operator that takes a
> > string parameter, and TimeSpan does not implement IConvertible. *For
> > example, the following does not complile:
>
> > >> * TimeSpan ts = "0:10:0";
>
> > TimeSpan does have a Parse() method that takes a string parameter,
> > i.e.
>
> > >> public static TimeSpan Parse(string s);
>
> > but I do not see how it is associated in the above sample code.
>
> > So again how does this code from the sample work in regards to
> > assigning a string
> > DefaultValue to a TimeSpan value? i.e.:
>
> > >> * DefaultValue = "0:10:0",
>
> > My guess is TimeSpan.Parse() is somehow being called, but where?
>
> I am not familiar with this attribute in particular, but the general
> way to do this sort of thing in .NET libraries is to use a type
> converter. TimeSpan has an associated TimeSpanConverter, which
> converts to/from string. It can be obtained using
> TimeConverter.GetConverter(typeof(TimeSpan)), which is probably what
> happens here.- Hide quoted text -
>
> - Show quoted text -

Hi Pavel,
Thanks for the help and info regarding TimeSpanConverter. I will post
what I learn about how this example works.
Keller

On Apr 27, 2:28*am, "Peter Duniho" <NpOeStPe...@nnowslpianmk.com>
wrote:
> On Sun, 26 Apr 2009 21:43:26 -0700, Keller <beyer...@aol.com> wrote:
> > [...]
> >>> * DefaultValue = "0:10:0",
>
> > My guess is TimeSpan.Parse() is somehow being called, but where?
>
> Like Pavel, I don't have a specific answer for you. *But, note that you*
> can inspect the .NET implementation yourself and see how it works. *With *
> Red Gate's Reflector, you can browse around the .NET DLLs. *An easier way *
> is to enable source-code download in Visual Studio, set a break-point on *
> the property's setter, and then see what led up to the default value being *
> set.
>
> Note that TimeSpan is one of five special-cased types supported for *
> configuration elements (Int32, Int64, regex String, and plain String being *
> the other four). *So it wouldn't surprise me too much to see some code in *
> the configuration-management implementation that simply special-cases the*
> type and performs the necessary Parse() (or possibly the TimeSpanConverter *
> as Pavel suggests).
>
> Pete

Hi Pete,
Thanks for the help and info about the special-cased types.

I did set a break point on the property's setter, but I don't think it
gets called (I will double check tonight). i.e.:

public class ConfigurationSection :
System.Configuration.ConfigurationSection
{
[ConfigurationProperty("maxDateTime", DefaultValue =
"0:10:0")]
public System.DateTime MaxDateTime
{
get { return (System.DateTime)this
["maxDateTime"]; }
set { this["maxDateTime"] = value; } // << Does
not appear to be called by constructor to set DefaultValue
}

[ConfigurationProperty("maxIdleTime", DefaultValue =
"0:10:0")]
public TimeSpan MaxIdleTime
{
get { return (TimeSpan)this["maxIdleTime"]; }
set { this["maxIdleTime"] = value; } // << Does
not appear to be called by constructor to set DefaultValue
}
}

I have been meaning to install Reflector, but I want to do a drive
image of my system first (I also have the
mobile SDK installed). I also plan to install the "Configuration
Section Designer" tool available on CodePlex,
i.e. http://csd.codeplex.com/.

Thanks again for the reply, I will post what I learn about setting
DefaultValues.
Keller