TDocVariant Serious Problem with Add(...

itSDS · 2014-10-06 12:16:25

Hi AB atm we encounter a serious(german: merkwürdig) Problem using TDocVariant

var
  doc : variant;
begin
  TDocVariant.New(doc);
  doc.Fehler := _Obj([]);
  doc.Fehler.Add('testfehler', true);
  assert(doc.fehler.testfehler = true, 'Fehler mit TDocVariant');
end;

On my developer Computer it works. Now we startet the programm in another computer and the assertion fails.

the Value of doc.fehler.testfehler is false

Very serious is that i get this error also sometimes in my debugger. But i didn't find the reason for this.

May you can help if you tell me how to debug it or where i have to set a breakpoint to inspect code.

Best Regards

itSDS · 2014-10-06 13:01:01

Solved the Problem with a cast:

DocVariantData(doc.fehler).AddValue('testfehler', true);

I found something about pseudo methods in syncommons.pas - But it seem's not to work in release mode on XE7 ?!

ab · 2014-10-06 15:47:26

DocVariantData or DocVariantDataSafe will always be faster than late binding.
Of course, the following sounds safer and better:

 doc.Fehler := _Obj(['testfehler',true]);

Or even

 doc.Fehler := _Obj([]);
  doc.Fehler.testfehler := true;

But there was some random issue with parameters when using late-binding for Unicode Version of Delphi.
Even Delphi 2007 is failing passing the value... and doc.Fehler.Add('testfehler', '3') will just trigger an OutOfMemory error!

The pseudo-methods are indeed pretty unstable...
I'm afraid this is not an issue with SynCommons, but with the Delphi RTL itself...

itSDS · 2014-10-07 13:55:55

Hi AB ty for your response.

we'll use DocVariantData now to Add Values. Cause we have to Add multiple Values to doc.fehler we have to call the AddValue direkt.
I havent't digged as deep as you in the RTL but would it be more Safe to remove the Pseudo - Functions ?

warleyalex · 2015-09-02 03:32:19

Something that I couldn't understand:

var
LDocVariant: variant;

begin
LDocVariant := _JsonFast('{ "Person": { "First": { "name" : "Alex" } } }');
LDocVariant.Person.Next := _ObjFast(['age', 31]); // this does not work for me

expected output:
{"Person":{"First":{"name":"Alex"},"Next":{"age":31}}}
--------------------------------------------------------------------------------

LDocVariant := _Json('{"name":?,"year":?}',[],['warleyalex',1982]); //this does not work - Ordinal type required

expected output:
{"name":"warleyalex","year":1982}

warleyalex · 2015-09-02 12:26:21

a) to add a JSON object content {"age":31} into {"Person":{"First":{"name":"Alex"}}} is works fine if you assign LDocVariant.Person.Next := LDocVariant1;

b) to produce valid JSON content from a given set of values identified by ? is better use _JsonFmt.

mORMot Open Source

#1 2014-10-06 12:16:25

TDocVariant Serious Problem with Add(...

#2 2014-10-06 13:01:01

Re: TDocVariant Serious Problem with Add(...

#3 2014-10-06 15:47:26

Re: TDocVariant Serious Problem with Add(...

#4 2014-10-07 13:55:55

Re: TDocVariant Serious Problem with Add(...

#5 2015-09-02 03:32:19

Re: TDocVariant Serious Problem with Add(...

#6 2015-09-02 12:26:21

Re: TDocVariant Serious Problem with Add(...

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