WPF组合框无响应

Question

I am calling data from a WCF service and populating a combo box in my WPF application. As soon as I navigate to the location of the Combo box the page freezes or sometimes I get to open the combo box but then it also freezes?

WPF

 private async void Window_Loaded(object sender, RoutedEventArgs e)
        {
            using (TruckServiceClient TSC = new TruckServiceClient())
            {
                await LoadPhase(TSC, cmbtest);

            }

    private async Task LoadPhase (TruckServiceClient TSC, ComboBox combobox)
    {
        List<Phasetems> phasetems = new List<Phasetems>();
        foreach (var item in await TSC.GetphaseAsync())
            phasetems.Add(new Phasetems { Phase = item.Phase });
        combobox.ItemsSource = (phasetems.ToArray());
        combobox.IsEnabled = true;
        combobox.SelectedIndex = 1;
    }

    public class Phasetems
    {
        public int Id { get; set; }

        public string Phase { get; set; }

        public override string ToString()
        {
            return Phase;
        }
    }

WCF

public List<RPhases> Getphase()
        {
            List<RPhases> phases = new List<RPhases>();
            List<RPhases> dbphase;

            using (TruckDb db = new TruckDb())
                dbphase = db.RPhases.Where(x => x.Id != null).ToList();
            foreach (var a in dbphase)
            {
                var items = new RPhases
                {
                   Id = a.Id,
                   Phase = a.Phase 
                };
                phases.Add(items);
            }
            return phases;
        }

Answer 1

The code you posted is correct and doesn´t create that ui blocking behaviour (as far as I can see).

Make sure nothing else is blocking the ui thread. Try it without the service call to see whether it still blocks it.

You can use Visual Studio break feature to step into running code and find out where it is.