convert an object to string and back (in a culture independent fashion)

[Lloyd Dupont]

to store user preference in our application we have an 'hand written' XML
file. (as opposed to XmlSerializer written one, which crash sometimes, on
some user's computer, for some unknown reason.. but I'm digressing)

In this XML file I store object value, which I convert to string (when
writting) and from string (when reading) with a couple of simple function
which (should) do a reversible conversion (using TypeConverter) (functions
below).

Unfortunately, for some Enum, (namely System.Windows.Forms.Keys) I got a
culture dependent string, even though I specify CultureInfo.InvariantCulture
as an argument in my ConvertXXX method with the TypeConverter. Even using
'new CultureInfo("en")' do not fix this behavior.

Any tip on how to fix these function (below) so they provide a truly culture
independent reversible object=>string=>object mechanism?
================================================== =
public static bool TryGetStringValue<T>(object val, out string ret)
{
if (val is string)
{
ret = (string)val;
return true;
}
TypeConverter tc = TypeDescriptor.GetConverter(typeof(T));
if (tc == null)
{
ret = val.ToString();
return false;
}
try
{
ret = tc.ConvertToString(null, CultureInfo.InvariantCulture, val);
return true;
}
catch (ArgumentException) { }
catch (NotSupportedException) { }
ret = val.ToString();
return false;
}
public static bool TryGetTValue<T>(object val, out T tval)
{
if (val is T)
{
tval = (T)val;
return true;
}
TypeConverter tc = TypeDescriptor.GetConverter(typeof(T));
if (tc == null)
{
tval = default(T);
return false;
}
if (!tc.IsValid(val))
{
tval = default(T);
return false;
}
try
{
tval = (T)tc.ConvertFrom(null, CultureInfo.InvariantCulture, val);
return true;
}
catch (ArgumentException) { }
catch (NotSupportedException) { }
tval = default(T);
return false;
}
================================================== =

[Marc Gravell]

If you look at KeysConverter in "reflector", and look at Initialize()
and ConvertTo(), you'll see that it gets the values from
SR.GetString(), which calls ResourceManager.GetString passing a "null"
culture, which in turn causes the system to use the CurrentUICulture.

So; perhaps you could take a memento of the current UI culture, make
your call and swap back? something like (untested, where Test2 does
the conversion):

static readonly CultureInfo fixedCulture =
CultureInfo.InvariantCulture;
static void Test() {
CultureInfo memento =
Thread.CurrentThread.CurrentUICulture;
if (memento == fixedCulture) {
Test2();
} else {
try {
Thread.CurrentThread.CurrentUICulture =
fixedCulture;
Test2();
} finally {
Thread.CurrentThread.CurrentUICulture = memento;
}
}
}

Also - note that TypeConverter can also be specified against an
individual property (not just a type), and the conversion can be
dependent on the instance. You may or may not wish to consider using
ITypeDescriptorContext to give this information to the converter.

Marc

[Lloyd Dupont]

Thanks for your answer....
I think I will try a special case for enum...
Other converter can't be that stupid!

--
Regards,
Lloyd Dupont
NovaMind Software
Mind Mapping at its best
www.nova-mind.com
"Marc Gravell" <ma**********@gmail.coma écrit dans le message de
news:11*********************@n59g2000hsh.googlegro ups.com...

If you look at KeysConverter in "reflector", and look at Initialize()
and ConvertTo(), you'll see that it gets the values from
SR.GetString(), which calls ResourceManager.GetString passing a "null"
culture, which in turn causes the system to use the CurrentUICulture.

So; perhaps you could take a memento of the current UI culture, make
your call and swap back? something like (untested, where Test2 does
the conversion):

static readonly CultureInfo fixedCulture =
CultureInfo.InvariantCulture;
static void Test() {
CultureInfo memento =
Thread.CurrentThread.CurrentUICulture;
if (memento == fixedCulture) {
Test2();
} else {
try {
Thread.CurrentThread.CurrentUICulture =
fixedCulture;
Test2();
} finally {
Thread.CurrentThread.CurrentUICulture = memento;
}
}
}

Also - note that TypeConverter can also be specified against an
individual property (not just a type), and the conversion can be
dependent on the instance. You may or may not wish to consider using
ITypeDescriptorContext to give this information to the converter.

Marc

[Marc Gravell]

For the special case, try dropping back to EnumConverter ;-p

[Lloyd Dupont]

thanks, it did work great!! ;-)

--
Regards,
Lloyd Dupont
NovaMind Software
Mind Mapping at its best
www.nova-mind.com
"Marc Gravell" <ma**********@gmail.comwrote in message
news:%2****************@TK2MSFTNGP04.phx.gbl...

For the special case, try dropping back to EnumConverter ;-p