WPF MVVM - Binding DataGrid to ObservableCollection of Model

Question

I am pretty new to WPF MVVM, so pardon me if I understood MVVM concepts wrongly.

I have a DataGrid in my View, which I have bound the ItemsSource to an ObservableCollection<M> in the ViewModel. The M class is a Model class. However, the M class has bool properties, which are to be displayed in the DataGrid as "Yes/No" strings.

Currently, I am using a Converter to convert the bool value to string. But, it just feels wrong for the ViewModel to expose a list (ObservableCollection) of a Model to the View. I have also read that in MVVM, conversions should be done at ViewModel. So, what is the right way to implement this the MVVM way for a DataGrid?

Answer 1

In an ideal world, you would wrap your Model objects in their own ViewModel so that your ObservableCollection contains a ViewModel type with those bool Model properties converted to Yes/No string properties.

However, in a pragmatic world, if you are not editing those values, I wouldn't bother except to note that if you are exposing many of those bool properties and have many thousands of rows, you will take a performance hit on rendering the grid while the DataGrid instantiates a Converter per property and row.

Answer 2

Using converters is not a wrong way. As per my suggestion, you should bind the data as you're doing now and in the view you can create and use a BoolToStringConverter for converting the boolean value to yes or no.