WPF ComboBox SelectionChanged event to command not firing

Bind SelectedValue to a Property on the view model.

In the Property set{...} block do your logic there or call

ListTypeComboSelectionChangedCmdExec(value)

See Binding ComboBox SelectedItem using MVVM

This is a really old question, but I'll answer for anyone who are interested later.

In my case, I use handler in the code behind and connect it to ModelView as below.

var viewModel = (MyViewModel)DataContext;
if (viewModel.MyCommand.CanExecute(null))
    viewModel.MyCommand.Execute(null);

Please check this link: Call Command from Code Behind