How to Validate TextBox content with pattern?

Valid with the following method in C # with a WPF window a text that should only accept valid names, as well as accept 2 names but no more, such as the following:

Correct examples:

• Alejandro
• Richard Yordy

Erroneous examples:

• 2Alejandro24
• Teresa de jesus

Code

  if (e.Key == Key.Delete || e.Key == Key.Back)
            {
                if (tbNombre.Text.Length >= 1|| tbNombre.Text.Length  ==0)
                {
                    nombre = tbNombre.Text;
                }
            }
            else if (Regex.IsMatch(tbNombre.Text, "^([a-zA-Z]{1,10}[ ]?[a-zA-Z]{0,7})$"))
            {
                nombre = tbNombre.Text;
            }
            else if (tbNombre.Text.Length != 0)
            {
                tt.Content = "No se aceptan numeros";
                tbNombre.ToolTip = tt;
                tt.IsOpen = true;
                int cursor = tbNombre.SelectionStart;
                tbNombre.Text = nombre;
                timer.Tick += new EventHandler(delegate (object timerSender, EventArgs timerArgs)//Para desaparecer el tooltip en un determinado tiempo
                {
                    tt.IsOpen = false;

                });
                if (cursor >= 0)
                {
                    if (cursor == 0)
                    {
                        tbNombre.SelectionStart = cursor;
                    }
                    else
                    {
                        tbNombre.SelectionStart = cursor - 1;
                    }
                }

            }

I solve it in this way which validates with form is written to prevent invalid data being entered such as numbers. I would like to know if there is any way to improve this to implement it in other TextBox