How to create an unqualified catch block in Dynamics AX ?
This is said dev help for AX2009sp1, but there is no example of it. All valid catch blocks need the exception type as mandatory parameter, for instance:
catch(exception::error)
{
:
}
have I missed something?
br,
You should leave the catch clause without parameter.
try
{
//...
}
catch
{
//...
}
Here is an excelent screencast on exception handling:
http://channel9.msdn.com/posts/mfp/Exception-handling-in-X/
I don't know AX, but I can offer some suggestions; you could try omitting the exception parameter all together (i.e. catch() {...}, or using the most generally type possible for the exception parameter (i.e. object or the equivalent in your language). That's at least how it works in many other languages.
"One strategy is to have the last catch statement leave the exception type unspecified"
http://msdn.microsoft.com/en-us/library/aa893385.aspx
Related
In Visual Studio there is a possibility to mute an exception when it happens in particular place, e.g. We are aware that there is some NullRefereneceException in Calculator.cs and we still want to catch those types of exceptions when thrown from all other places in code, but Calculator.cs.
How it looks like in VS:
Is such a feature available in Rider?
I wasn't able to find a solution to your question.
The only thing I found is to not break on a specific exception type - but that's unrelated to the line.
For example, let's take the following code:
public class OtherClass
{
public void ThrowNullReferenceException()
{
try
{
throw new NullReferenceException();
}
catch (Exception e)
{
Console.WriteLine(e);
throw;
}
}
}
With the following Exception Settings, the handled NullReferenceException gets swallowed:
Maybe you can get in contact with Rider support.
As of now the feature is not yet available, but there is a Youtrack ticket for this feature.
In my project I have this:
ParallelFlux<Device> flux = Flux.fromIterable(children)
.delayElements(Duration.ofMillis(10))
.parallel(18)
.runOn(Schedulers.elastic(), 10)
.doOnNext(c -> recursiveValidationThroughoutChildren(c, tracker)
});
Where recursiveValidationThroughoutChildren is a method with this declaration:
boolean recursiveValidationThroughoutChildren(Device d, NodeChangesTracker tracker) throws Exception;
What I don't understand is how to handle the exception thrown by this last method. I would like the exception to be propagated outside the ParallelFlux.
Is it possible? What is the correct way to handle it?
I followed the link #Rozart suggested, but I could not apply the solution as it is explained. I had to change it a bit:
ParallelFlux<Device> flux = Flux.fromIterable(children)
.delayElements(Duration.ofMillis(10))
.parallel(18)
.runOn(Schedulers.elastic(), 10)
.doOnNext(child -> {
try {
recursiveValidationThroughoutChildren(child, tracker);
} catch (Exception ex) {
Flux.error(ex);
}
});
The change is needed because the ParallelFlux does not support the "handle" method, so I had to add a try catch and relaunch the exception with a Flux.error.
I don't know if it is good practice, but it is the only way I got it work.
In most programming languages, there is a finally block that can be placed after try or catch block like this :
try {
sensitiveFunction();
} catch (Exception e) {
executedWhenFailed();
} finally {
alwaysExecuted();
}
But we can execute the same code without finally block like that :
try {
sensitiveFunction();
} catch (Exception e) {
executedWhenFailed();
}
alwaysExecuted();
So, why does finally block exist? Anyone have an example that finally block is required ?
Thanks
Even these examples aren't equivalent: if sensitiveFunction() throws something which doesn't extend Exception but Error instead, alwaysExecuted won't be executed without finally (please don't try to "fix" this by catching Throwable).
Or say executedWhenFailed() itself throws an exception: it's quite common to rethrow an exception from a catch block after adding some information. Again, alwaysExecuted() won't be executed in the second snippet.
Or suppose you have return sensitiveFunction(); instead of just a call. Etc. etc.
finally exists so that code can always be run, without regard to if you caught the exception or not.
Sometimes you want to just use try and finally together:
allocate()
try:
do_something_with_allocated()
finally:
deallocate()
In the above example, it lets you 100% confidently clean up a resource that was opened above without regard for any exceptions that may be propagating up.
If you throw a new exception in your catch block, you will eventually (after that exception has been handled) end up in your finally block. But not in the line after your catch.
Just throw an exception in executedWhenFailed, in your first example alwaysExecuted will be executed, in the second it wil not.
The finally block is executed even if there is a return statement in the catch() block.
(Example in JavaScript)
function foo() {
try {
throw "first"
} catch(err){
console.log(err)
return "third"
} finally {
console.log("second") // Called before return in catch block
}
return "Never reached"
}
console.log(foo())
If i know that only one function (take in the example) will throw the exception, what could be the correct way, of the following options?
All in the try block:
try
{
while (someCondition)
{
take();
anotherFunction();
}
}
catch(Exceotion e)
{
//some instructions
}
Inside the block only the function that throw the exception:
while (someCondition)
{
try
{
take();
}
catch....
{
//some instructions
}
anotherFunction();
}
I would use the first way because it's clearer, but there is an explicit rule about this?
Thanks!
The two ways do very different things and depending on what you need the code to do, either can be correct.
In the first example, anotherFunction is not called if there was an exception.
In the second example, the exception is being dealt with in the catch block, and anotherFunction will be executed afterwards.
Along the same lines, in the first example, an exception aborts the whole while loop, whereas in the second example it aborts only a single iteration and continues the loop with the next iteration.
I'm using LLBLGen and I have some code like so:
if (onlyRecentMessages)
{
messageBucket.PredicateExpression.Add(MessageFields.DateEffective >= DateTime.Today.AddDays(-30));
}
var messageEntities = new EntityCollection<MessageEntity>();
using (var myAdapter = PersistenceLayer.GetDataAccessAdapter())
{
myAdapter.FetchEntityCollection(messageEntities, messageBucket);
}
I'm currently getting a SqlException on the FetchEntityCollection line. The error is:
System.Data.SqlClient.SqlException: The incoming tabular data stream (TDS) remote procedure call (RPC) protocol stream is incorrect. Too many parameters were provided in this RPC request. The maximum is 2100.
but that's a side note. What I actually want to be able to do is include the generated SQL in a custom exception in my code. So for instance something like this:
using (var myAdapter = PersistenceLayer.GetDataAccessAdapter())
{
try
{
myAdapter.FetchEntityCollection(messageEntities, messageBucket);
}
catch (SqlException ex)
{
throw new CustomSqlException(ex, myAdapter.GeneratedSqlFromLastOperation);
}
}
Of course, there is no such property as GeneratedSqlFromLastOperation. I'm aware that I can configure logging, but I would prefer to have the information directly in my stack track / exception so that my existing exception logging infrastructure can provide me with more information when these kinds of errors occur.
Thanks!
Steve
You should get an ORMQueryExecutionException, which contains the full query in the description. The query's execute method wraps all exceptions in an ORMQueryExecutionException and stores the query in the description.
ps: please, if possible ask llblgen pro related questions on our forums, as we don't monitor stackoverflow frequently. Thanks. :)