DispatcherHelper for MVVM framework

   1:      /// <summary>

   2:      /// Helper class for dispatcher operations on the UI thread.

   3:      /// </summary>

   4:      public static class DispatcherHelper

   5:      {

   6:          /// <summary>

   7:          /// Gets a reference to the UI thread's dispatcher, after the <see cref="Initialize()"/>

   8:          /// method has been called on the UI thread.

   9:          /// </summary>

  10:          public static Dispatcher UIDispatcher { get; private set; }

  11:          /// <summary>

  12:          ///     Executes an action on the UI thread. If this method is called from the UI

  13:          ///     thread, the action is executed immendiately. If the method is called from

  14:          ///     another thread, the action will be enqueued on the UI thread's dispatcher

  15:          ///     and executed asynchronously.

  16:          ///     For additional operations on the UI thread, you can get a reference to the

  17:          ///     UI thread's dispatcher thanks to the property <see cref="UIDispatcher"/>

  18:          /// </summary>

  19:          /// <param name="action">The action that will be executed on the UI thread.</param>

  20:          public static void CheckBeginInvokeOnUI(Action action)

  21:          {

  22:              if (UIDispatcher == null || UIDispatcher.CheckAccess())

  23:              {

  24:                  action();

  25:              }

  26:              else

  27:              {

  28:                  UIDispatcher.BeginInvoke(action);

  29:              }

  30:          }

  31:          public static void CheckBeginInvokeOnUI<T>(Action<T> action, T arg)

  32:          {

  33:              if (UIDispatcher == null || UIDispatcher.CheckAccess())

  34:              {

  35:                  action(arg);

  36:              }

  37:              else

  38:              {

  39:                  UIDispatcher.BeginInvoke(action, arg);

  40:              }

  41:          }

  42:          /// <summary>

  43:          ///    This method should be called once on the UI thread to ensure that the <see cref="UIDispatcher"/>

  44:          ///    property is initialized.

  45:          ///    In a Silverlight application, call this method in the Application_Startup

  46:          ///    event handler, after the MainPage is constructed.

  47:          ///    In WPF, call this method on the static App() constructor.

  48:          /// </summary>

  49:          public static void Initialize()

  50:          {

  51:              UIDispatcher = Dispatcher.CurrentDispatcher;

  52:          }

  53:      }