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

> On Mon, Mar 15, 2010 at 10:04 PM, Sacha Barber <sacha.bar...@gmail.com>wrote:

>> I do not like the idea of the Binding not firing.

>> On Mon, Mar 15, 2010 at 9:56 PM, Marlon Grech <marlongr...@gmail.com>wrote:

>>> may I ask why you guys prefer option 1? Just for curiosity...
>>> Regards
>>> Marlon
>>> WPF Blog - http://marlongrech.wordpress.com/
>>> Microsoft MVP for Client App

>>> On Mon, Mar 15, 2010 at 9:20 PM, Peter O'Hanlon <pete.ohan...@gmail.com>wrote:

>>>> Same here.

>>>> On Mon, Mar 15, 2010 at 9:18 PM, Sacha Barber <sacha.bar...@gmail.com>wrote:

>>>>> I prefer option 1 actually

>>>>> 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

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

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