Question

With MVVM and WPF what would be a good/straightforward way to handle opening and closing new windows and dialogs? Opening and closing should be driven by the ViewModel right? But the ViewModel should not know about the view …

Answer 1

I usually use interfaces for this.
For example, if i want to edit a record in a separate window, i have an interface IEditingProvider<TViewModel>, which i can implement somewhere else and then pass an interface reference to the constructor of my ViewModel. The EditingProvider might just do something like this:

class MyRecordEditingProvider: IEditingProvider<MyRecordViewModel>
{
    // Implementation of generic interface method
    public void Edit(MyRecordViewModel model) {
        EditWindow edit = new EditWindow(); 
        edit.DataContext = model;
        edit.ShowDialog();
    }
}