ENH Keep state in Page's Breadcrumbs

[sabina-talipova]

Description

• Additional get parameters in Breadcrumbs links

Parent issue

• GridField. Create Unique URLs for Gridfield state. silverstripe-admin#1314

[GuySartorelli]

Don't think we need this PR

[GuySartorelli]

I don't think we want this - we probably only want this on the "back" button in the breadcrumb rather than each link. That's handled in GridFieldDetailForm_ItemRequest::getBackLink().

If we do want this to apply to each link, we should do this from the GridFieldDetailForm_ItemRequest::Breadcrumbs() method. This already has a list of all of the breadcrumbs ($items = $this->popupController->Breadcrumbs($unlinked);) which we can loop through like this:

foreach ($items as $item) {
    if ($item->Link) {
        $item->Link = $this->gridField->addOtherGridfieldStateToURL($item->Link);
    }
}

That way we only have this in the context of a gridfield, instead of arbitrarily adding all params to every breadcrumb.