> On Mar 15, 7:33 pm, Marlon Grech <marlongr...@gmail.com> wrote:
> > something like this... but I need to do something else so that its
> cooler...

> > The Idea is that rather then setting an attached property to every
> element
> > you want to control you just set it once and find that element by using
> WPF
> > Namescopes.

> > Attached is a prototype... yet I just built this now... did not test
> it...
> > and probably I have bugs all over the place.,... I just did it to show
> you
> > what I mean

> > Regards
> > Marlon
> > WPF Blog -http://marlongrech.wordpress.com/
> > Microsoft MVP for Client App

> > On Mon, Mar 15, 2010 at 5:50 PM, Josh Smith <flappleja...@gmail.com>
> wrote:
> > > What do you have in mind?

> > > On Mon, Mar 15, 2010 at 10:46 AM, Marlon Grech <marlongr...@gmail.com
> >wrote:

> > >> mmm... interesting approach... what about leveraging Namescopes for
> such a
> > >> thing?

> > >> Regards
> > >> Marlon
> > >> WPF Blog -http://marlongrech.wordpress.com/
> > >> Microsoft MVP for Client App

> > >> On Mon, Mar 15, 2010 at 3:12 PM, Peter O'Hanlon <
> pete.ohan...@gmail.com>wrote:

> > >>> Sounds good. As far as the FocusScopes go, there shouldn't be any
> issues,
> > >>> but it's an edge case to consider (I've been bitten too many times by
> custom
> > >>> FocusScopes).

> > >>> On Mon, Mar 15, 2010 at 3:08 PM, Josh Smith <flappleja...@gmail.com
> >wrote:

> > >>>> Thanks Pete. I was thinking that there could be an attached property
> of
> > >>>> type bool that is set on an element, instead of setting
> ValidatedProperty.
> > >>>>  When set, that attached property figures out which property on the
> element
> > >>>> to monitor, such as Text on a TextBox.  This would make it easier
> than
> > >>>> having to specify the property, though that would still be an option
> if you
> > >>>> need to specify it.

> > >>>> I'll have to look into FocusScopes, though I don't see any issues
> there
> > >>>> (I might be overlooking something...).

> > >>>> Josh

> > >>>> On Mon, Mar 15, 2010 at 6:31 AM, Peter O'Hanlon <
> pete.ohan...@gmail.com
> > >>>> > wrote:

> > >>>>> The only thing that stands out to me is that this is going to have
> to
> > >>>>> be applied in a lot of places in a typical LOB application, so that
> might be
> > >>>>> a little bit tedious. What effects do FocusScope's have here? I'll
> need to
> > >>>>> play around with this a bit just to make sure there aren't any edge
> cases
> > >>>>> that occur (I'm primarily thinking of cases where loss of focus to
> a
> > >>>>> menu/toolbar triggers the validation but the parent FocusScope has
> changed
> > >>>>> from the textbox).

> > >>>>> Pete

> > >>>>>   On Mon, Mar 15, 2010 at 2:24 PM, Josh Smith <
> flappleja...@gmail.com>wrote:

> > >>>>>> Thanks.  Any pitfalls or gotchas sticking their heads out?

> > >>>>>> On Mon, Mar 15, 2010 at 1:03 AM, Peter O'Hanlon <
> > >>>>>> pete.ohan...@gmail.com> wrote:

> > >>>>>>> I like it - I know that it feels "dirty", but it's actually
> pretty
> > >>>>>>> darn cool.

> > >>>>>>>  On Mon, Mar 15, 2010 at 3:54 AM, Josh Smith <
> flappleja...@gmail.com
> > >>>>>>> > wrote:

> > >>>>>>>> A while back Dr. WPF graced us with his clever hack of
> controlling
> > >>>>>>>> input focus from VM objects.  It involved hijacking the VM's
> IDataErrorInfo
> > >>>>>>>> implementation, and doing all sorts of evil-genius stuff to make
> the input
> > >>>>>>>> caret move to the correct element.  Today while I was *trying*
> to
> > >>>>>>>> read a great novel, I couldn't stop thinking about another way
> to control
> > >>>>>>>> input focus from a viewmodel object.

> > >>>>>>>> I put the novel down and did a quick spike of the idea.  The
> source
> > >>>>>>>> code is attached (rename it from .DOC to .ZIP since gmail is
> terrified of
> > >>>>>>>> ZIP files for some reason).  Here's the general idea...

> > >>>>>>>> Implement this interface on your VM class:

> > >>>>>>>>  /// <summary>
> > >>>>>>>> /// Implemented by a ViewModel that needs to control
> > >>>>>>>> /// where input focus is in a View.
> > >>>>>>>> /// </summary>
> > >>>>>>>> public interface IFocusController
> > >>>>>>>> {
> > >>>>>>>>     /// <summary>
> > >>>>>>>>     /// Raised when the input focus should move to
> > >>>>>>>>     /// a control whose 'active' dependency property
> > >>>>>>>>     /// is bound to the specified property.
> > >>>>>>>>     /// </summary>
> > >>>>>>>>     event EventHandler<MoveFocusEventArgs> MoveFocus;
> > >>>>>>>> }

> > >>>>>>>> Next, in your VM object (which might implement IDataErrorInfo),
> do
> > >>>>>>>> something like this to support a Save button:

> > >>>>>>>>  public ICommand SaveCommand
> > >>>>>>>> {
> > >>>>>>>>     get { return new RelayCommand(this.Save); }
> > >>>>>>>> }

> > >>>>>>>> void Save()
> > >>>>>>>> {
> > >>>>>>>>     if (this.HasError)
> > >>>>>>>>     {
> > >>>>>>>>         // The Error property knows which property is invalid.
> > >>>>>>>>         this.RaiseMoveFocus(this.Error);
> > >>>>>>>>     }
> > >>>>>>>>     else
> > >>>>>>>>     {
> > >>>>>>>>         // Save to database...
> > >>>>>>>>         System.Windows.MessageBox.Show("Saved");
> > >>>>>>>>     }
> > >>>>>>>> }

> > >>>>>>>> bool HasError
> > >>>>>>>> {
> > >>>>>>>>     get { return _validatedProperties.Any(prop =>
> > >>>>>>>> !String.IsNullOrEmpty(this[prop])); }
> > >>>>>>>> }

> > >>>>>>>>  public event EventHandler<MoveFocusEventArgs> MoveFocus;

> > >>>>>>>> void RaiseMoveFocus(string focusedProperty)
> > >>>>>>>> {
> > >>>>>>>>     var handler = this.MoveFocus;
> > >>>>>>>>     if (handler != null)
> > >>>>>>>>     {
> > >>>>>>>>         handler(this, new MoveFocusEventArgs(focusedProperty));
> > >>>>>>>>     }
> > >>>>>>>> }

> > >>>>>>>> Lastly, in your View, use my terribly(?) named attached property
> to
> > >>>>>>>> specify which DP on your elements is bound to the validated
> property of the
> > >>>>>>>> VM, for example:

> > >>>>>>>>  <TextBox
> > >>>>>>>>     Text="{Binding Path=FirstName, ValidatesOnDataErrors=True}"
> > >>>>>>>>     *local:FocusControl.ValidatedProperty="TextBox.Text"*
> > >>>>>>>>     />

> > >>>>>>>> I'm not sure that I like this approach yet.  It's a pretty
> important
> > >>>>>>>> topic, so I thought I'd share this out amongst the Disciples for
> feedback.

> > >>>>>>>> Thanks,
> > >>>>>>>> Josh

> > >>>>>>> --
> > >>>>>>> Peter O'Hanlon

> > >>>>> --
> > >>>>> Peter O'Hanlon

> > >>> --
> > >>> Peter O'Hanlon

> >  TestFocus.zip.doc
> > 140KViewDownload