Put/Get UploadField submitted image from custom Form -> Silverstripe 3.1 - image

Question

I have a small problem programming with the use of UploadField . I have created pages to make a light CMS on the FrontEnd. But I don't know how retrieve this image to the page «Update».
There is the code from the page «Create» :
$uploadField = new UploadField( 'ImageEvenement', 'Image' );
There is the code I tried to get working for the page «Update»
$evenID = Session::get('evenementID');
$evenement = Versioned::get_by_stage('PageCalendrierEvenement', 'Stage')->byID($evenID);
..
$SavedImage = File::get()->byID($evenement->ImageEvenementID)
$uploadField = new UploadField( 'ImageEvenement', 'Image', $SavedImage );
How can I retrieve the submitted image to $SavedImage ? My idea to get the ID from File don't work.
Another method :
$SavedImage = $evenement->ImageEvenement();
If I dump data from $SavedImage I'm viewing :
Image Object
(
[destroyed] =>
[model:protected] => DataModel Object
(
[customDataLists:protected] => Array
(
)
)
[record:protected] => Array
(
[ClassName] => Image
[Created] => 2015-07-15 14:41:24
[LastEdited] => 2015-07-16 15:03:25
[Name] => images.jpg
[Title] => images
[Filename] => assets/Membres/9/calendrier/images.jpg
[ShowInSearch] => 1
[ParentID] => 15
[OwnerID] => 9
[ID] => 22
[RecordClassName] => Image
)
[changed:DataObject:private] => Array
(
)
[original:protected] => Array
(
[ClassName] => Image
[Created] => 2015-07-15 14:41:24
[LastEdited] => 2015-07-16 15:03:25
[Name] => images.jpg
[Title] => images
[Filename] => assets/Membres/9/calendrier/images.jpg
[ShowInSearch] => 1
[ParentID] => 15
[OwnerID] => 9
[ID] => 22
[RecordClassName] => Image
)
[brokenOnDelete:protected] =>
[brokenOnWrite:protected] =>
[components:protected] =>
[unsavedRelations:protected] =>
[sourceQueryParams:protected] =>
[failover:protected] =>
[customisedObject:protected] =>
[objCache:ViewableData:private] => Array
(
)
[class] => Image
[extension_instances:protected] => Array
(
[BetterButtonDataObject] => BetterButtonDataObject Object
(
[owner:protected] =>
[ownerBaseClass:protected] => DataObject
[ownerRefs:Extension:private] => 0
[class] => BetterButtonDataObject
)
[SiteTreeFileExtension] => SiteTreeFileExtension Object
(
[owner:protected] =>
[ownerBaseClass:protected] => File
[ownerRefs:Extension:private] => 0
[class] => SiteTreeFileExtension
)
[Hierarchy] => Hierarchy Object
(
[markedNodes:protected] =>
[markingFilter:protected] =>
[_cache_numChildren:protected] =>
[owner:protected] =>
[ownerBaseClass:protected] => File
[ownerRefs:Extension:private] => 0
[class] => Hierarchy
)
)
[beforeExtendCallbacks:protected] => Array
(
)
[afterExtendCallbacks:protected] => Array
(
)
)
Any idea?
class PageCalendrierEvenement extends Page {
private static $db = array(
"Titre" => "Varchar(50)",
"DateDepart" => "Date",
"DateFin" => "Date",
);
private static $has_one = array(
'Creator' => 'Member',
'ImageEvenement' => 'Image',
);
..
}
Thank you!

Answer 1

has one relations need the "ID" suffix in the name of the relation (as it's saved to db...), e.g.
$uploadField = new UploadField( 'ImageEvenementID', 'Image', $SavedImage );
then it should save automatically.
OR, what i do for a single relation:
$imageField = UploadField::create('ImageEvenement', 'Image');
$imageField->setAllowedFileCategories('image');
$imageField->setAllowedMaxFileNumber(1);
hope that helps.

Answer 2

My code works fine but are not clean and not using SilverStripe function classes. The reason for non working saving images to dataobject, is because that I have not use :
$form->saveInto($evenement)
I would like to thank you Wmk for give me the get method to fill form with values on another post :
$form->loadDataForm($evenement)
Finaly, all works fine now!

Answer 3

Finaly after long time brain searching, I have found the trick! The command to use with UploadField is setValue($value) with fileIDs include with it. My final code is :
$evenement = Versioned::get_by_stage('PageCalendrierEvenement', 'Stage')->byID($evenID);
...
$uploadField = new UploadField( 'ImageEvenement', 'Image' );
$data['ImageID'] = $evenement->ImageEvenement()->ID;
$fileIDs[]=$data['ImageID'];
$uploadField->setValue(array('Files' => $fileIDs));
Thats it!