public IMemento Restore() {
// Before
drawableContainer.Invalidate();
ChangeFieldHolderMemento oldState = new ChangeFieldHolderMemento(drawableContainer, fieldToBeChanged);
fieldToBeChanged.Value = oldValue;
// After
drawableContainer.Invalidate();
return oldState;
}
public IMemento Restore()
{
// Before
drawableContainer.Invalidate();
ChangeFieldHolderMemento oldState = new ChangeFieldHolderMemento(drawableContainer, fieldToBeChanged);
fieldToBeChanged.Value = oldValue;
// After
drawableContainer.Invalidate();
return(oldState);
}
public bool Merge(IMemento otherMemento)
{
ChangeFieldHolderMemento other = otherMemento as ChangeFieldHolderMemento;
if (other != null)
{
if (other.drawableContainer.Equals(drawableContainer))
{
if (other.fieldToBeChanged.Equals(fieldToBeChanged))
{
// Match, do not store anything as the initial state is what we want.
return(true);
}
}
}
return(false);
}