Freeze Core(Boolean) Method
Makes this Timeline unmodifiable or determines whether it can be made unmodifiable.
protected: override bool FreezeCore(bool isChecking);
protected override bool FreezeCore (bool isChecking);
override this.FreezeCore : bool -> bool
Protected Overrides Function FreezeCore (isChecking As Boolean) As Boolean
true to check if this instance can be frozen;
false to freeze this instance.
isChecking is true, this method returns
true if this instance can be made read-only, or
false if it cannot be made read-only.
isChecking is false, this method returns
true if this instance is now read-only, or
false if it cannot be made read-only, with the side effect of having begun to change the frozen status of this object.
Do not call this method directly (except when calling base in an implementation). This method is called internally by Freeze.
Notes to Inheritors
Timeline implementers must override this method when the class contains data that is not stored using dependency properties.
A typical implementation would call base, then call the static Freeze() method on all Freezable typed properties that the class contains, returning
true only if all properties were frozen (or could have been frozen, in the case of passing through a
false value for