Set focus on TextBox in WPF from view model

Question

I have a TextBox and a Button in my view.

Now I am checking a condition upon button click and if the condition turns out to be false, displ

Answer 1

I think the best way is to keep the MVVM principle clean, so basically you must use the Messenger Class provided with the MVVM Light and here is how to use it:

in your viewmodel(exampleViewModel.cs):write the following

 Messenger.Default.Send("focus", "DoFocus");

now in your View.cs(not the XAML the view.xaml.cs) write the following in the constructor

 public MyView()
        {
            InitializeComponent();

            Messenger.Default.Register(this, "DoFocus", doFocus);
        }
        public void doFocus(string msg)
        {
            if (msg == "focus")
                this.txtcode.Focus();
        }

that method owrks just fine and with less code and maintaining MVVM standards