Как заставить слайдер двигаться с течением времени?

Question

Как каждую секунду сверять значение переменной, которая меняется каждую секунду, с положением слайдера (WPF), и изменять в зависимости от значения этой самой переменной.

Ни dispatcher invoke, ни таймеры не помогли.

Появляется ошибка: "этот элемент уже занят основным потоком"

Answer 1

На просторах интернета нашел удобный класс для работы с объектами из разных потоков. Общий ответ используй класс Dispatcher.

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
namespace SP_Unsafe_DLL
{
    public class SafeGuiWpf
    {
        public static object GetTag(Control C)
        {
            if (C.Dispatcher.CheckAccess()) return C.Tag;
            else return C.Dispatcher.Invoke(new Func<Control, object>(GetTag), C);
        }
        public static string GetText(TextBox TB)
        {
            if (TB.Dispatcher.CheckAccess()) return TB.Text;
            else return (string)TB.Dispatcher.Invoke(new Func<TextBox, string>(GetText), TB);
        }
        public static string GetText(ComboBox TB)
        {
            if (TB.Dispatcher.CheckAccess()) return TB.Text;
            else return (string)TB.Dispatcher.Invoke(new Func<ComboBox, string>(GetText), TB);
        }
    public static string GetText(PasswordBox TB)
    {
        if (TB.Dispatcher.CheckAccess()) return TB.Password;
        else return (string)TB.Dispatcher.Invoke(new Func&lt;PasswordBox, string&gt;(GetText), TB);
    }

    public static void SetText(TextBlock TB, string Str)
    {
        if (TB.Dispatcher.CheckAccess()) TB.Text = Str;
        else TB.Dispatcher.Invoke(new Action&lt;TextBlock, string&gt;(SetText), TB, Str);
    }
    public static void SetText(TextBox TB, string Str)
    {
        if (TB.Dispatcher.CheckAccess()) TB.Text = Str;
        else TB.Dispatcher.Invoke(new Action&lt;TextBox, string&gt;(SetText), TB, Str);
    }
    public static void AppendText(TextBox TB, string Str)
    {
        if (TB.Dispatcher.CheckAccess())
        {
            TB.AppendText(Str);
            TB.ScrollToEnd(); // scroll to end?
        }
        else TB.Dispatcher.Invoke(new Action&lt;TextBox, string&gt;(AppendText), TB, Str);
    }
    public static bool? GetChecked(CheckBox Ck)
    {
        if (Ck.Dispatcher.CheckAccess()) return Ck.IsChecked;
        else return (bool?)Ck.Dispatcher.Invoke(new Func&lt;CheckBox, bool?&gt;(GetChecked), Ck);
    }
    public static void SetChecked(CheckBox Ck, bool? V)
    {
        if (Ck.Dispatcher.CheckAccess()) Ck.IsChecked = V;
        else Ck.Dispatcher.Invoke(new Action&lt;CheckBox, bool?&gt;(SetChecked), Ck, V);
    }
    public static bool GetChecked(MenuItem Ck)
    {
        if (Ck.Dispatcher.CheckAccess()) return Ck.IsChecked;
        else return (bool)Ck.Dispatcher.Invoke(new Func&lt;MenuItem, bool&gt;(GetChecked), Ck);
    }
    public static void SetChecked(MenuItem Ck, bool V)
    {
        if (Ck.Dispatcher.CheckAccess()) Ck.IsChecked = V;
        else Ck.Dispatcher.Invoke(new Action&lt;MenuItem, bool&gt;(SetChecked), Ck, V);
    }
    public static bool? GetChecked(RadioButton Ck)
    {
        if (Ck.Dispatcher.CheckAccess()) return Ck.IsChecked;
        else return (bool?)Ck.Dispatcher.Invoke(new Func&lt;RadioButton, bool?&gt;(GetChecked), Ck);
    }
    public static void SetChecked(RadioButton Ck, bool? V)
    {
        if (Ck.Dispatcher.CheckAccess()) Ck.IsChecked = V;
        else Ck.Dispatcher.Invoke(new Action&lt;RadioButton, bool?&gt;(SetChecked), Ck, V);
    }

    public static void SetVisible(UIElement Emt, Visibility V)
    {
        if (Emt.Dispatcher.CheckAccess()) Emt.Visibility = V;
        else Emt.Dispatcher.Invoke(new Action&lt;UIElement, Visibility&gt;(SetVisible), Emt, V);
    }
    public static Visibility GetVisible(UIElement Emt)
    {
        if (Emt.Dispatcher.CheckAccess()) return Emt.Visibility;
        else return (Visibility)Emt.Dispatcher.Invoke(new Func&lt;UIElement, Visibility&gt;(GetVisible), Emt);
    }
    public static bool GetEnabled(UIElement Emt)
    {
        if (Emt.Dispatcher.CheckAccess()) return Emt.IsEnabled;
        else return (bool)Emt.Dispatcher.Invoke(new Func&lt;UIElement, bool&gt;(GetEnabled), Emt);
    }
    public static void SetEnabled(UIElement Emt, bool V)
    {
        if (Emt.Dispatcher.CheckAccess()) Emt.IsEnabled = V;
        else Emt.Dispatcher.Invoke(new Action&lt;UIElement, bool&gt;(SetEnabled), Emt, V);
    }

    public static void SetSelectedItem(Selector Ic, object Selected)
    {
        if (Ic.Dispatcher.CheckAccess()) Ic.SelectedItem = Selected;
        else Ic.Dispatcher.Invoke(new Action&lt;Selector, object&gt;(SetSelectedItem), Ic, Selected);
    }
    public static object GetSelectedItem(Selector Ic)
    {
        if (Ic.Dispatcher.CheckAccess()) return Ic.SelectedItem;
        else return Ic.Dispatcher.Invoke(new Func&lt;Selector, object&gt;(GetSelectedItem), Ic);
    }
    public static int GetSelectedIndex(Selector Ic)
    {
        if (Ic.Dispatcher.CheckAccess()) return Ic.SelectedIndex;
        else return (int)Ic.Dispatcher.Invoke(new Func&lt;Selector, int&gt;(GetSelectedIndex), Ic);
    }

    delegate MessageBoxResult MsgBoxDelegate(Window owner, string text, string caption, MessageBoxButton button, MessageBoxImage icon);
    public static MessageBoxResult MsgBox(Window owner, string text, string caption, MessageBoxButton button, MessageBoxImage icon)
    {
        if (owner.Dispatcher.CheckAccess()) return MessageBox.Show(owner, text, caption, button, icon);
        else return (MessageBoxResult)owner.Dispatcher.Invoke(new MsgBoxDelegate(MsgBox), owner, text, caption, button, icon);
    }

    public static double GetRangeValue(RangeBase RngBse)
    {
        if (RngBse.Dispatcher.CheckAccess()) return RngBse.Value;
        else return (double)RngBse.Dispatcher.Invoke(new Func&lt;RangeBase, double&gt;(GetRangeValue), RngBse);
    }
    public static void SetRangeValue(RangeBase RngBse, double V)
    {
        if (RngBse.Dispatcher.CheckAccess()) RngBse.Value = V;
        else RngBse.Dispatcher.Invoke(new Action&lt;RangeBase, double&gt;(SetRangeValue), RngBse, V);
    }

    public static T CreateWindow&lt;T&gt;(Window Owner) where T : Window, new()
    {
        if (Owner.Dispatcher.CheckAccess())
        {
            var Win = new T(); // Window created on GUI thread
            Win.Owner = Owner;
            return Win;
        }
        else return (T)Owner.Dispatcher.Invoke(new Func&lt;Window, T&gt;(CreateWindow&lt;T&gt;), Owner);
    }

    public static bool? ShowDialog(Window Dialog)
    {
        if (Dialog.Dispatcher.CheckAccess()) return Dialog.ShowDialog();
        else return (bool?)Dialog.Dispatcher.Invoke(new Func&lt;Window, bool?&gt;(ShowDialog), Dialog);
    }

    public static void SetDialogResult(Window Dialog, bool? Result)
    {
        if (Dialog.Dispatcher.CheckAccess()) Dialog.DialogResult = Result;
        else Dialog.Dispatcher.Invoke(new Action&lt;Window, bool?&gt;(SetDialogResult), Dialog, Result);
    }

    public static Window GetWindowOwner(Window window)
    {
        if (window.Dispatcher.CheckAccess()) return window.Owner;
        else return (Window)window.Dispatcher.Invoke(new Func&lt;Window, Window&gt;(GetWindowOwner), window);
    }

} // END CLASS: SafeGuiWpf

}

Answer 2

В общем я покопался немного в событиях, написал такой код и всё заработало:

private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        _timer.Interval = TimeSpan.FromMilliseconds(1000);
        _timer.Tick += new EventHandler(sinchronyzeSliderAndVideoSession);
        _timer.Start();
    }
private void sinchronyzeSliderAndVideoSession(object sender, EventArgs e)
{
    VideoSlider.Value = VideoPlayer.Position.TotalSeconds;
}