Question

I’ve got a silverlight view (for lack of a better work) with some text boxes on it that have their values bound to entities exposed via a DomainService query (using silverlight 4, EF 4, and RIA Domain Services). I’ve got everything wired up and saving correctly based on values changing, but I need to include who is making the changes as well as the field bound to the control.

XAML:

   <TextBox Name="txtComment" Text="{Binding Comment, Mode=TwoWay}" ></TextBox>

Initialization:

  _dataContext.Load(accountingItemValues, (lo) =>
            {   
                ... Bind other boxes to entities
                this.txtComment.DataContext = _dataContext.AccountingItemValues.First().STARS_DistrictInputData;
            }, null);

Is there a good way of getting a handle to the entity that the control is bound to? I tried an implicit cast of the (myEntity)control.DataContext, but that didn’t work out. I’d like to be able to change the UpdatedBy property of the STARS_DistrictInputData as well as the Comment property explicitly bound in the xaml.

Update: The userId is available at the page, so I don’t need to query for it.

Answer 1

I found a work-around, but it seems hacky:

In the page I set up a private instantiation of the entity I wanted to bind to:

MyEntity _myEntity;

XAML:

<TextBox Name="txtComment" Text="{Binding Comment, Mode=TwoWay}" ></TextBox>

Initialization:

 _dataContext.Load(accountingItemValues, (lo) =>
            {   
                ... Bind other boxes to entities
                _myEntity = _dataContext.AccountingItemValues.First().STARS_DistrictInputData;

                this.txtComment.DataContext = _myEntity;
            }, null);

Then I changed the .UpdatedBy property of the entity on the changed event of my textbox. Is there a way to do the double binding in the XAML?