Problem with XmlSerializer - error reflecting type

[Peter Webb]

Its been working fine for ages, I spend a couple of days on unrelated parts
of the system, and I can no longer write files (or read old ones).

The error message I get is "There was an error reflecting type
WindowsApplication1.Form1.savestructure'.".

Here is the code, which has worked fine for ages:

public class savestructure
{
public List<textaslot> alist;
public int speed, size;
public int squareorcircle;
}


(textaslot is an awful class, with lots of public members. However, I
haven't added very much into it in the last few days, and taking what I have
doesn't seem to help, although it was a lot of work to try. Nor can I
understand why this would fail on write, so its not a compatibility issue.)


..
..

private void savethisconfig()
{
savestructure thissave = new savestructure();
thissave.alist = slotcollection;
thissave.speed = (int)speedUpDown.Value;
thissave.squareorcircle = mainrotatortype;
thissave.size = (int)sizeUpDown.Value;
serialiseandsave(thissave);
}

public void serialiseandsave(savestructure allslots)
{

XmlSerializer mySerializer = new
XmlSerializer(typeof(savestructure));

... and that's where it crashes.

This is really spooking me, as it also means I can't load any of the dozens
of files I have created. I have no idea where to go after getting this
error - what to try.

Any suggestions?

 

[Marc Gravell]

First - check the seccessive inner-exceptions; there might be more
detail available.

Second - for deserializing this, you might want the list to be auto-
created in the constructor; IIRC, generally (for IList<T> etc) it just
calls .Add() for each child item - it doesn't expect to create the
list first [but this would impact deserialization, not serialization].

Third - very hard to tell without something short and reproducable.

Marc

 

[Richard Blewett]

Its been working fine for ages, I spend a couple of days on unrelated
parts of the system, and I can no longer write files (or read old ones).

The error message I get is "There was an error reflecting type
WindowsApplication1.Form1.savestructure'.".

Here is the code, which has worked fine for ages:

public class savestructure
{
public List<textaslot> alist;
public int speed, size;
public int squareorcircle;
}


(textaslot is an awful class, with lots of public members. However, I
haven't added very much into it in the last few days, and taking what I
have doesn't seem to help, although it was a lot of work to try. Nor can I
understand why this would fail on write, so its not a compatibility
issue.)


.
.

private void savethisconfig()
{
savestructure thissave = new savestructure();
thissave.alist = slotcollection;
thissave.speed = (int)speedUpDown.Value;
thissave.squareorcircle = mainrotatortype;
thissave.size = (int)sizeUpDown.Value;
serialiseandsave(thissave);
}

public void serialiseandsave(savestructure allslots)
{

XmlSerializer mySerializer = new
XmlSerializer(typeof(savestructure));

... and that's where it crashes.

This is really spooking me, as it also means I can't load any of the
dozens of files I have created. I have no idea where to go after getting
this error - what to try.

Any suggestions?

Have you generated the serialization assembly using sgen.exe?

If thats the case you may be picking up the old one which no longer
serializes correctly

--
Regards

Richard Blewett
DevelopMentor
http://www.dotnetconsult.co.uk/weblog2

 

[Peter Webb]

First - check the seccessive inner-exceptions; there might be more
detail available.

And when I did, it identified that I didn't have a parameterless constructor
for one type, and that fixed it.

I didn't even know you could get this information - when you click on the
"show inner exception" hyperlink it takes you to a useless MSDN page -
thankyou for pointing it out to me.

 

[Marc Gravell]

and that fixed it

good to hear

it takes you to a useless MSDN page

Yes; that window isn't as useful as it could be; those links are very
easy (too easy) to click when you actually mean "*show* me the
exception" (which is the "View Detail..." link). Personally, I'd like
it if the IDE simply listed each nested Message in turn, with perhaps
a right-click option on each to show the MSDN information about that
specific exception.

Marc