private static bool trySpawnOnStaThread <TWindow, TArgs>(StaWindowThreadParams <TWindow, TArgs> myParams)
where TWindow : Window
{
Dispatcher myDispatcher = null;
try {
SynchronizationContext.SetSynchronizationContext(
new DispatcherSynchronizationContext(
(myDispatcher = Dispatcher.CurrentDispatcher)));
myParams.Window = myParams.Constructor(
myParams.ConstructorArgs != null
? myParams.ConstructorArgs()
: default(TArgs));
myParams.Window.Closed += WindowHelper.windowClosed;
} catch (Exception ex) {
Trace.TraceError(
$"{typeof(WindowHelper)} {nameof(WindowHelper.CreateWindowOnNewStaThread)}: "
+ $"exception within ThreadStart. {ex}");
if (myParams.Window != null)
{
myParams.Window.Closed -= WindowHelper.windowClosed;
try {
myParams.Window.Close();
} catch {
// Ignored
}
}
try {
myDispatcher?.InvokeShutdown();
} catch {
// Ignored
}
myParams.Window = null;
myParams.Error = ex;
return(false);
} finally {
myParams.Gate.Set();
}
return(true);
}
/// <summary>
/// Creates a new STA Background Thread, which sets a <c>SynchronizationContext</c>
/// with a <c>Dispatcher</c>. Then constructs a new <c>Window</c> on the Thread,
/// using the <c>constructor</c> <c>Func</c> and any <c>constructorArgs</c>. Then
/// the Thread runs the <c>Dispatcher</c> and this method returns the <c>Window</c>.
/// The <c>Dispatcher</c> listens for <c>window.Closed</c> and invokes
/// <c>BeginInvokeShutdown</c>. The <c>constructorArgs</c> is provided as a <c>Func</c>
/// so that it will be invoked on the <c>Window's</c> Thread: the object you return
/// is passed to your <c>constructor</c> (and has been created on that Thread). This
/// may be null.
/// </summary>
/// <typeparam name="TWindow">Your Window Type.</typeparam>
/// <typeparam name="TArgs">Constructor's argument type</typeparam>
/// <param name="constructor">Construct and return your Window.</param>
/// <param name="constructorArgs">Optional args for your constructor Func. If this
/// argument is not null, it will be invoked on the new Thread, and the result
/// is passed to your <c>constructor</c>. If this is null, your constructor receives
/// <c>default(TArgs)</c>.</param>
/// <param name="error">This must be checked. If not null, the result will
/// be null.</param>
public static TWindow CreateWindowOnNewStaThread <TWindow, TArgs>(
Func <TArgs, TWindow> constructor,
Func <TArgs> constructorArgs,
out Exception error) where TWindow : Window
{
using (StaWindowThreadParams <TWindow, TArgs> threadParams
= new StaWindowThreadParams <TWindow, TArgs>(constructor, constructorArgs)) {
Thread newWindowThread = new Thread(
tp => {
if (WindowHelper.trySpawnOnStaThread((StaWindowThreadParams <TWindow, TArgs>)tp))
{
Dispatcher.Run();
}
});
newWindowThread.SetApartmentState(ApartmentState.STA);
newWindowThread.IsBackground = true;
newWindowThread.Start(threadParams);
threadParams.Gate.WaitOne();
error = threadParams.Error;
return(threadParams.Window);
}
}
