src/NetStandard/Collections/Synchronization/src/CollectionModificationIterationTools.cs
/// <summary>
/// Checks a modification that is about to move items existing items. Thus it throws an exception if no old items are present.
/// </summary>
/// <param name="modification"></param>
/// <exception cref="ArgumentException">Member <see cref="ICollectionModificationInfo.OldItemsCount"/> is null.</exception>
Checks a modification that is about to move items existing items. Thus it throws an exception if no old items are present.
Checks a modification that is about to move items existing items . Thus it throws an exception if no old items are present .
public static void CheckMove(ICollectionModificationInfo modification)
        {
            if (modification.OldItemsCount is null) {
                throw new ArgumentException("Old items were not given while moving.");
            }
        }
public static void CheckMove ( ICollectionModificationInfo modification ) { if ( modification . OldItemsCount is null ) { throw new ArgumentException ( " " ) ; } }
Checks a modification that is about to move items existing items.
Checks a modification that is about to move items existing items .
Member  is null.
Member is null .
modification
ICollectionModificationInfo
None