On Apr 19, 2:28 pm, VisualHint <cadil...@gmail.com> wrote:
> Hi,
>
> Let's say that in my own custom control (derived from Control), I have
> a property Value of type object. My goal is to store in this property
> a DateTime or null. In order to store and edit a DateTime, I assign to
> it the DateTimeConverter and DateTimeEditor attributes. All is fine at
> runtime. However at design time, when I set an empty string in the
> PropertyGrid (which is accepted by the grid), the serializer refuses
> to write something like:
>
> myControl.Value = null;
>
> Instead it writes:
>
> myControl.Value = new System.DateTime(((long)(0)));
>
> Am I obliged to write my own serializer or is there something else I
> can do ?
>
> Thank you for your help
>
> Nicolas

On Apr 19, 3:10 pm, VisualHint <cadil...@gmail.com> wrote:
> I should add that the first time it is serialized, if Value is null it
> is serialized correctly (myControl.Value = null).
> But as soon as I edit the property and set it to a date, then erase
> the property in the grid with an empty string, it is serialized as
> System.DateTime(((long)(0))); instead of null.
>
> Nicolas
>
> On Apr 19, 2:28 pm, VisualHint <cadil...@gmail.com> wrote:
>
> > Hi,
>
> > Let's say that in my own custom control (derived from Control), I have
> > a property Value of type object. My goal is to store in this property
> > a DateTime or null. In order to store and edit a DateTime, I assign to
> > it the DateTimeConverter and DateTimeEditor attributes. All is fine at
> > runtime. However at design time, when I set an empty string in the
> > PropertyGrid (which is accepted by the grid), the serializer refuses
> > to write something like:
>
> > myControl.Value = null;
>
> > Instead it writes:
>
> > myControl.Value = new System.DateTime(((long)(0)));
>
> > Am I obliged to write my own serializer or is there something else I
> > can do ?
>
> > Thank you for your help
>
> > Nicolas

wrote:
> On Apr 19, 3:10 pm, VisualHint <cadil...@gmail.com> wrote:
>
>
>
> > I should add that the first time it is serialized, if Value is null it
> > is serialized correctly (myControl.Value = null).
> > But as soon as I edit the property and set it to a date, then erase
> > the property in the grid with an empty string, it is serialized as
> > System.DateTime(((long)(0))); instead of null.
>
> > Nicolas
>
> > On Apr 19, 2:28 pm, VisualHint <cadil...@gmail.com> wrote:
>
> > > Hi,
>
> > > Let's say that in my own custom control (derived from Control), I have
> > > a property Value of type object. My goal is to store in this property
> > > a DateTime or null. In order to store and edit a DateTime, I assign to
> > > it the DateTimeConverter and DateTimeEditor attributes. All is fine at
> > > runtime. However at design time, when I set an empty string in the
> > >PropertyGrid(which is accepted by the grid), the serializer refuses
> > > to write something like:
>
> > > myControl.Value = null;
>
> > > Instead it writes:
>
> > > myControl.Value = new System.DateTime(((long)(0)));
>
> > > Am I obliged to write my own serializer or is there something else I
> > > can do ?
>
> > > Thank you for your help
>
> > > Nicolas
>
> Your problem probably stems from the fact that DateTime is a
> "structure" not a "class" and cannot be assigned the value null. Are
> you using Nullable<DateTime> (also written DateTime?). Whenever we
> use DateTime and need to represent "null", we either use
> Nullable<DateTime> or simply assign it to DateTime.MinValue, and in
> our data mapping code translate MinValue to DbNull and visa-versa.
>
> I've noticed that there are several cases where the default
> serialization can be a little finicky. In those cases, it is probably
> a better idea to have your class extend ISerializable and implement
> the serialization yourself. That way you know exactly what it is
> doing.