error "Object reference not set to an instance of an object"

Question

hello, 

I have this error, when I do that:  pageTitle.Text = listFilterTitle.NomeEscola;

in my code I can pass a value and compare...

this is my code: 

 List<Escola> ListTitle = new List<Escola>();

   db.RunInTransaction(() =>
                    {
          
                        ListTitle = db.Query<Escola>("Select NomeEscola from Escola");


                        
                    });

var listFilterTitle = ListTitle.Where(escola => escola.ID_Escola.ToString() == idEscola).FirstOrDefault();


  pageTitle.Text = listFilterTitle.NomeEscola;

thanks