Josh Smith's MVVM Tabs get unselected

Question

I have an MVVM application using tabs like Josh Smith's example. Each TabItem (View) represents an individual ViewModel.

On some Views there are DataGrids that are bound to ObservableCollections. So far everything works fine. But when I start to edit a data grid, e.g. by typing into a cell, and before hitting 'enter' to submit the changes, switch to another tab, I cannot really get back to the previous tab. The Tab content changes but the tabitem remains unselected. I guess I somehow have to stop the editing mode of the datagrid, but how do I do that in an MVVM app? For an ICollectionViewSource I know I could do it like this

  IEditableCollectionView list = (ListCollectionView)this.ItemsView;
  if (list.IsEditingItem) list.CommitEdit();
  if (list.IsAddingNew) list.CommitNew();

but I cant do this for an ObservableCollection. Do I have to change the Binding to a view of the observable collection or is there another way?

Would you be able to produce a small code sample demonstrating the problem in a new project? — Rachel

Jens H Jens H · Accepted Answer · 2012-08-09T15:04:03

For exiting the edit mode of the grid automatically, have a look at this SO question: WPF DataGrid - How to automatically exit Edit Mode?

I would also suggest to have a look at the IEditableObject interface for the model classes that are bound to be edited within the grid. This gives you a consistent way to implement adding data and edit them for changes (or the rollback of changes) on the object's data.

IEditableObject requires you to implement the following methods:

BeginEdit()
CancelEdit()
EndEdit()

The DataGrid is already designed to work with IEditableObject objects out of the box.

Dr. WPF has written a nice article about the interface here: ItemsControl: 'E' is for Editable Collection and there is some sample code for using IEditableObjects with a dataGrid in this MSDN article: How to: Implement Validation with the DataGrid Control

Josh Smith's MVVM Tabs get unselected

1 Answers