/// <summary>
/// Raises an event safely, ensuring that all handlers are called on the proper thread, and any exceptions do not prevent other handlers being called.
/// </summary>
/// <param name="handler">The event to raise.</param>
/// <param name="sender">The sender of the event.</param>
/// <param name="e">Event arguments for the event.</param>
/// <exception cref="AggregateException">Thrown if any handlers raise exceptions, with the exceptions raised captured in the <see cref="AggregateException.InnerExceptions"/> property.</exception>
/// <remarks>Temporarily made internal, as the use cases for this class really aren't clear enough to be confident of a suitable implementation of ISynchronizedObject.</remarks>
public static void SafeRaise(this Delegate handler, ISynchronizedObject sender, EventArgs e)
{
sender.ThrowIfNull(nameof(sender));
if (handler is null)
{
return;
}
if (handler.Method.GetParameters() is ParameterInfo[] handlerParams && (handlerParams.Length != 2 ||
!handlerParams[0].ParameterType.IsAssignableFrom(sender.GetType()) ||
!handlerParams[1].ParameterType.IsAssignableFrom(e?.GetType())))
{
throw new ArgumentException("Sender and event args must match handler parameter types.");
}
List <Exception> raisedExceptions = null;
sender.SynchronizationContext.Post(
state =>
{
foreach (Delegate del in handler.GetInvocationList())
{
try
{
del.DynamicInvoke(sender, e);
}
catch (TargetInvocationException ex) when(ex.InnerException is Exception)
{
if (raisedExceptions is null)
{
raisedExceptions = new List <Exception>();
}
raisedExceptions.Add(ex.InnerException);
}
}
}, null);
// Check list of exceptions is either still null, or not empty.
Debug.Assert(raisedExceptions is null || raisedExceptions.Any(), "Empty list of exceptions after handling event.");
if (raisedExceptions is List <Exception> )
{
throw new AggregateException(Properties.Resources.SafeRaiseExceptionMessage, raisedExceptions);
}
}
/// <summary>
/// Raises an event safely, ensuring that all handlers are called on the proper thread, and any exceptions do not prevent other handlers being called.
/// </summary>
/// <param name="handler">The event to raise.</param>
/// <param name="sender">The sender of the event.</param>
/// <param name="e">Event arguments for the event.</param>
/// <exception cref="AggregateException">Thrown if any handlers raise exceptions, with the exceptions raised captured in the <see cref="AggregateException.InnerExceptions"/> property.</exception>
/// <remarks>Temporarily made internal, as the use cases for this class really aren't clear enough to be confident of a suitable implementation of ISynchronizedObject.</remarks>
public static void SafeRaise(this EventHandler handler, ISynchronizedObject sender, EventArgs e)
{
sender.ThrowIfNull(nameof(sender));
if (handler is null)
{
return;
}
List <Exception> raisedExceptions = null;
sender.SynchronizationContext.Post(
state =>
{
foreach (Delegate del in handler.GetInvocationList())
{
try
{
del.DynamicInvoke(sender, e);
}
catch (TargetInvocationException ex) when(ex.InnerException is Exception)
{
if (raisedExceptions is null)
{
raisedExceptions = new List <Exception>();
}
raisedExceptions.Add(ex.InnerException);
}
}
}, null);
// Check list of exceptions is either still null, or not empty.
Debug.Assert(raisedExceptions is null || raisedExceptions.Any(), "Empty list of exceptions after handling event.");
if (raisedExceptions is List <Exception> )
{
throw new AggregateException(Properties.Resources.SafeRaiseExceptionMessage, raisedExceptions);
}
}
