> 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