> On Mon, Mar 15, 2010 at 8:43 PM, Marlon Grech <marlongr...@gmail.com>wrote:

>> P.S sorry for ugly code and all that but the code I produced is just to
>> show you guys the idea ....

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

>>   On Mon, Mar 15, 2010 at 8:42 PM, Marlon Grech <marlongr...@gmail.com>wrote:

>>> Attached is take 2...

>>> Basically I hate it when my ViewModel has to implement all these
>>> interfaces... It feels like back in Java days to me...

>>> so the idea here is to still use namescopes but leverage the databinding
>>> capabilities of WPF... so that you can do something like this

>>> <Grid focusStuff:FocusedBehaviourTake2.FocusElement="{Binding Focus}">

>>> and in the VM

>>> Save = new RelayCommand( x => Focus= "Name");

>>> Basically in the ViewModel you set a property that exposes the element
>>> that should get focus. The attached behavior (which accepts binding) will
>>> get triggered when the property changes. THERE IS ONE SIDE EFFECT OF THIS.
>>> Basically if the viewmodel sets the Focus property to be the same the
>>> attached behavior will not get triggered again... this might be a show
>>> stopper for this idea... what do you guys think?

>>> which approach would you like best?

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

>>>   On Mon, Mar 15, 2010 at 8:25 PM, Daniel Vaughan <dbvaug...@gmail.com>wrote:

>>>> Good thinking Marlon. As Pete said, very innovative.

>>>> 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

>  --
> Sacha Barber
> sacha.bar...@gmail.com