/// <summary>
/// Rescues a Value if it has Valid References
/// </summary>
/// <param name="valueDeleted">It's the UniqueID of the IStateObject being deleted</param>
/// <param name="branchUniqueID">It's the Root object that started the Deletion process.</param>
/// <returns>True if the Value had valid references and it was rescued from deletion.</returns>
internal bool RescueValue(string objToRemoveUniqueID, string branchUniqueID = null, bool allowUnAttachedReferences = true, bool isDispose = false, IFormBaseViewModel formBaseViewModel = null, HashSet <string> _objectsToBeValidatedAfterDisposeHashSet = null)
{
if (branchUniqueID == null)
{
branchUniqueID = objToRemoveUniqueID;
}
var referencesTable = GetObjectReferencesTable(objToRemoveUniqueID);
if (referencesTable != null)
{
referencesTable.ValidateReferences(branchDeleted: branchUniqueID, validateUnAttached: !allowUnAttachedReferences);
//If the object to be removed is a ListItem AND the referencesTable's count is major than zero,
//then we have a special block for handling this situation.
if (UniqueIDGenerator.IsListItem(objToRemoveUniqueID) && referencesTable.Count > 0)
{
//If the referenced object is IViewModel, or IDisposableDependencyControl,
//we should never rescue them.
if (isDispose && referencesTable.IsReferencedObjectAnIDisposableDependencyControl)
{
return(false);
}
//If there are some valid references, we should rescue it.
else if (HasValidReferencesForListItem(referencesTable, objToRemoveUniqueID, _objectsToBeValidatedAfterDisposeHashSet))
{
RescuedValueUniqueIdHashSet.Add(objToRemoveUniqueID);
return(true);
}
//otherwise, we shouldn't resue it
else
{
return(false);
}
}
else if (referencesTable.Count > 0)//No references
{
bool res = TransferValueToReference(branchUniqueID, referencesTable, isDispose: isDispose, formBaseViewModel: formBaseViewModel);
if (res)
{
RescuedValueUniqueIdHashSet.Add(objToRemoveUniqueID);
}
return(res);
}
}
//Given this kind of uniqueID: x#y#KIXYZ
// We have to validate if KIXYZ has been rescued previously,
// if this KIXYZ has been rescued, we should skip this uniqueID
var accessPathIndex = objToRemoveUniqueID.LastIndexOf(UniqueIDGenerator.UniqueIdSeparator);
if (accessPathIndex > 0)
{
var ancestorUID = objToRemoveUniqueID.Substring(accessPathIndex + 1);
var canRescue = RescuedValueUniqueIdHashSet.Contains(ancestorUID) && !_stateManager.IsInElementsToRemove(ancestorUID);
if (UniqueIDGenerator.IsListItem(ancestorUID) && canRescue)
{
return(true);
}
}
return(false);
}
private bool TransferValueToReference(string branchRemoved, ReferencesTable referencesTable, IStateObject elementToAdoptObj = null, bool isDispose = false, IFormBaseViewModel formBaseViewModel = null)
{
if (isDispose && referencesTable.IsReferencedObjectAnIDisposableDependencyControl)
{
return(false);
}
//If the elementToAdopt was not sent as a parameter let's calculate it.
if (elementToAdoptObj == null)
{
elementToAdoptObj = referencesTable.ReferencedObject;
}
string oldParentUniqueID = elementToAdoptObj.UniqueID;
//Entire windows won't be preserved.
if (elementToAdoptObj is IViewModel)
{
return(false);
}
//Let's get the reference candidate for the adoption.
var reference = GetReferenceValidForAdoption(referencesTable, false);
if (reference == null)
{
return(false);
}
var candidate = CalculateCandidateForAdoption(reference);
//The cadidates parent was already removed...Ciao
if (candidate == null)
{
return(false);
}
bool doNotRegisterIDSwitch = true;
if (formBaseViewModel == null)
{
formBaseViewModel = ViewManager.Instance.GetTopLevelObject(elementToAdoptObj) as IFormBaseViewModel;
}
if (formBaseViewModel != null)
{
doNotRegisterIDSwitch = formBaseViewModel.IsDisposing;
}
if (!(elementToAdoptObj is IDisposableDependencyControl) || (!isDispose && !doNotRegisterIDSwitch))
{
//The element won't belong to the parent anymore.
IStateObject elementsToBeAdopted = _stateManager.DettachObject(elementToAdoptObj, !doNotRegisterIDSwitch);
//We need to promote the object and attach it to the first candidate.
AdoptionInformation.StaticAdopt(candidate, elementsToBeAdopted);
////Let's update all the references
UpdateReferencesTables(oldParentUniqueID, elementToAdoptObj.UniqueID);
//Only foreign references allowed
referencesTable.RemoveReference(reference);
//We move the element to a substitute parent.
referencesTable.AttachedToParent = false;
//We had a succesfull adoption :)
return(true);
}
return(false);
}