UI线程中使用
public class SmartDispatcher
{ public static void BeginInvoke(Action action)
{ if (Deployment.Current.Dispatcher.CheckAccess() || DesignerProperties.IsInDesignTool)
{ action();
}
else { Deployment.Current.Dispatcher.BeginInvoke(action);
}
}
}
using System.ComponentModel; namespace System.Windows.Threading { /// /// A smart dispatcher system for routing actions to the user interface /// thread. /// public static class SmartDispatcher
{ /// /// A single Dispatcher instance to marshall actions to the user /// interface thread. /// private static Dispatcher _instance;
/// /// Backing field for a value indicating whether this is a design-time /// environment. /// private static bool? _designer;
/// /// Requires an instance and attempts to find a Dispatcher if one has /// not yet been set. /// private static void RequireInstance()
{ if (_designer == null)
{ _designer = DesignerProperties.IsInDesignTool;
}
// Design-time is more of a no-op, won't be able to resolve the // dispatcher if it isn't already set in these situations. if (_designer == true)
{ return; }
// Attempt to use the RootVisual of the plugin to retrieve a // dispatcher instance. This call will only succeed if the current // thread is the UI thread. try { _instance = Application.Current.RootVisual.Dispatcher;
}
catch (Exception e) { throw new InvalidOperationException("The first time SmartDispatcher is used must be from a user interface thread. Consider having the application call Initialize, with or without an instance.", e);
}
if (_instance == null)
{ throw new InvalidOperationException("Unable to find a suitable Dispatcher instance.");
}
}
/// /// Initializes the SmartDispatcher system, attempting to use the /// RootVisual of the plugin to retrieve a Dispatcher instance. /// public static void Initialize()
{ if (_instance == null)
{ RequireInstance();
}
}
/// /// Initializes the SmartDispatcher system with the dispatcher /// instance. /// /// The dispatcher instance. public static void Initialize(Dispatcher dispatcher)
{ if (dispatcher == null)
{ throw new ArgumentNullException("dispatcher");
}
_instance = dispatcher;
if (_designer == null)
{ _designer = DesignerProperties.IsInDesignTool;
}
}
/// /// /// /// public static bool CheckAccess()
{ if (_instance == null)
{ RequireInstance();
}
return _instance.CheckAccess(); }
/// /// Executes the specified delegate asynchronously on the user interface /// thread. If the current thread is the user interface thread, the /// dispatcher if not used and the operation happens immediately. /// /// A delegate to a method that takes no arguments and /// does not return a value, which is either pushed onto the Dispatcher /// event queue or immediately run, depending on the current thread. public static void BeginInvoke(Action a)
{ if (_instance == null)
{ RequireInstance();
}
// If the current thread is the user interface thread, skip the // dispatcher and directly invoke the Action. if (_instance.CheckAccess() || _designer == true)
{ a();
}
else { _instance.BeginInvoke(a);
}
}
}
}