public static string ToJson(
this object obj,
ExceptionHandlingMode exceptionHandlingMode = ExceptionHandlingMode.Throw)
{
var jsonSerializerSettings = ConfigureSettings();
return(Convert(obj, exceptionHandlingMode, data => JsonConvert.SerializeObject(data, jsonSerializerSettings)));
}
public static T FromJson <T>(
this string obj,
ExceptionHandlingMode exceptionHandlingMode = ExceptionHandlingMode.Throw)
{
var jsonSerializerSettings = ConfigureSettings();
return(Convert(obj, exceptionHandlingMode, data => JsonConvert.DeserializeObject <T>(data, jsonSerializerSettings)));
}
private static TResult Convert <TData, TResult>(
TData data,
ExceptionHandlingMode exceptionHandlingMode,
Func <TData, TResult> converter)
{
TResult result = default;
try
{
if (data != null)
{
result = converter(data);
}
}
catch (Exception)
{
if (exceptionHandlingMode == ExceptionHandlingMode.Throw)
{
throw;
}
}
return(result);
}
/// <summary>
/// Raises an event safely, making sure all handlers are called
/// even if some throw exceptions.
/// </summary>
/// <param name="handler"></param>
/// <param name="mode">An enum value specifying how exceptions
/// should be handled.</param>
/// <param name="args">A list of parameters to be passed to event
/// handlers.</param>
public static void SafeRaise(this Delegate handler, ExceptionHandlingMode mode, params object[] args)
{
SafeRaise(handler, mode, null, args);
}
/// <summary>
/// Raises an event safely, making sure all handlers are called
/// even if some throw exceptions, using the specified SynchronizationContext
/// instance to invoke handlers.
/// </summary>
/// <param name="handler"></param>
/// <param name="mode">An enum value specifying how exceptions
/// should be handled.</param>
/// <param name="syncContext">A SynchronizationContext instance
/// that should be used to invoke event handlers, or null if handlers
/// should be invoked on the calling thread.</param>
/// <param name="sender">The source of the event.</param>
/// <param name="e">An object containing data about the event.</param>
public static void SafeRaise(this Delegate handler, ExceptionHandlingMode mode, SynchronizationContext syncContext, object sender, EventArgs e)
{
SafeRaise(handler, mode, syncContext, sender, (object)e);
}
/// <summary>
/// Raises an event safely, making sure all handlers are called
/// even if some throw exceptions.
/// </summary>
/// <param name="handler"></param>
/// <param name="mode">An enum value specifying how exceptions
/// should be handled.</param>
/// <param name="sender">The source of the event.</param>
/// <param name="e">An object containing data about the event.</param>
public static void SafeRaise(this Delegate handler, ExceptionHandlingMode mode, object sender, EventArgs e)
{
SafeRaise(handler, mode, null, sender, (object)e);
}
/// <summary>
/// Raises an event safely, making sure all handlers are called
/// even if some throw exceptions, using the specified SynchronizationContext
/// instance to invoke handlers.
/// </summary>
/// <param name="handler"></param>
/// <param name="mode">An enum value specifying how exceptions
/// should be handled.</param>
/// <param name="syncContext">A SynchronizationContext instance
/// that should be used to invoke event handlers, or null if handlers
/// should be invoked on the calling thread.</param>
/// <param name="args">A list of parameters to be passed to event
/// handlers.</param>
public static void SafeRaise(this Delegate handler, ExceptionHandlingMode mode, SynchronizationContext syncContext, params object[] args)
{
// When using a SynchronizationContext, exceptions thrown by
// handlers cannot be caught and aggregated because they are called
// is an asynchronous fire-and-forget manner using SynchronizationContext.Post()
// (because SynchronizationContext.Send() is not supported on
// all target frameworks of a portable class library).
if (syncContext != null & mode == ExceptionHandlingMode.ThrowAll)
{
throw new ArgumentException("The 'syncContext' parameter must be null when the 'mode' parameter is ExceptionMode.ThrowAll. Catching and aggregating exceptions with asynchronous invocation is not supported.", nameof(syncContext));
}
// NOTE: Since the handler parameter was supplied by value, we
// do not need to explicitly make a temporary copy of it to uphold
// thread safety.
if (handler != null)
{
// Maintain a list of all exceptions thrown by registered event
// handlers.
List <Exception> exceptions = null;
if (mode == ExceptionHandlingMode.ThrowAll)
{
exceptions = new List <Exception>();
}
// If we determined handler signature compatibility once, there
// is no use doing it for each handler (if one handler matches,
// we can assume they all do).
var determinedCompatibility = false;
foreach (var aDelegate in handler.GetInvocationList())
{
// Copy to temporary variables for thread safety.
var tempHandler = aDelegate;
if (tempHandler == null)
{
continue;
}
if (!determinedCompatibility)
{
// Make sure the handler method is compatible with the EventHandler
// signature. There's no compile-time way of doing this, so a
// bit of reflection magic is necessary. Specifically, we check
// for the following things (more might be necessary):
// * The return type is void.
// * The number of parameters is equal to the number of parameters supplied to this method.
// * Each parameter can be assigned the value of its respective parameter supplied to this method.
var isCompatible = true;
var methodInfo = tempHandler.GetMethodInfo();
var returnValue = methodInfo.ReturnType;
var @params = methodInfo.GetParameters();
if (!ReferenceEquals(returnValue, typeof(void)) || @params.Length != args.Length)
{
isCompatible = false;
}
else
{
var argIndex = 0;
foreach (var arg in args)
{
if (arg != null && !@params[argIndex].ParameterType.GetTypeInfo().IsAssignableFrom(arg.GetType().GetTypeInfo()))
{
isCompatible = false;
break;
}
argIndex++;
}
}
if (!isCompatible)
{
throw new InvalidCastException("The handler signature of this event is not compatible with the supplied parameter types.");
}
determinedCompatibility = true;
}
try
{
void invokeFunc(object state) => tempHandler.DynamicInvoke(args);
// Invoke the handler asynchronously in the target synchronization
// context if one is specified, otherwise call the handler directly.
if (syncContext != null)
{
syncContext.Post(invokeFunc, null);
}
else
{
invokeFunc(null);
}
}
catch (TargetInvocationException ex)
{
// NOTE: This point will never be reached if syncContext is not null.
if (ex.InnerException == null)
{
continue;
}
// Employ different handling logic here depending on the specified
// exception mode.
switch (mode)
{
case ExceptionHandlingMode.Swallow:
// Nothing to do here.
break;
case ExceptionHandlingMode.ThrowAll:
exceptions.Add(ex);
break;
}
}
}
if (mode == ExceptionHandlingMode.ThrowAll)
{
throw new MulticastEventException("One or more registered event handlers threw exceptions.", exceptions.ToArray());
}
}
}
