/// <summary>
/// Construct a NotifyChangeRequestedEventArgs that describes a one-item change.
/// </summary>
/// <param name="action">The action that caused the event.</param>
/// <param name="changedItem">The item affected by the change.</param>
/// <param name="index">The index where the change occurred.</param>
public NotifyChangeRequestedEventArgs(NotifyChangeRequestedAction action, T changedItem, int index)
{
if ((action != NotifyChangeRequestedAction.Add) && (action != NotifyChangeRequestedAction.Remove) &&
(action != NotifyChangeRequestedAction.Reset))
{
throw new ArgumentException(SR.MustBeResetAddOrRemoveActionForCtor, nameof(action));
}
if (action == NotifyChangeRequestedAction.Reset)
{
if (changedItem != null)
{
throw new ArgumentException(SR.ResetActionRequiresNullItem, nameof(action));
}
if (index != -1)
{
throw new ArgumentException(SR.ResetActionRequiresIndexMinus1, nameof(action));
}
InitializeAdd(action, null, -1);
}
else
{
InitializeAddOrRemove(action, new T[] { changedItem }, index);
}
}
/// <summary>
/// Construct a NotifyChangeRequestedEventArgs that describes a multi-item change (or a reset).
/// </summary>
/// <param name="action">The action that caused the event.</param>
/// <param name="changedItems">The items affected by the change.</param>
/// <param name="startingIndex">The index where the change occurred.</param>
public NotifyChangeRequestedEventArgs(NotifyChangeRequestedAction action, IList <T> changedItems, int startingIndex)
{
if ((action != NotifyChangeRequestedAction.Add) && (action != NotifyChangeRequestedAction.Remove) &&
(action != NotifyChangeRequestedAction.Reset))
{
throw new ArgumentException(SR.MustBeResetAddOrRemoveActionForCtor, nameof(action));
}
if (action == NotifyChangeRequestedAction.Reset)
{
if (changedItems != null)
{
throw new ArgumentException(SR.ResetActionRequiresNullItem, nameof(action));
}
if (startingIndex != -1)
{
throw new ArgumentException(SR.ResetActionRequiresIndexMinus1, nameof(action));
}
InitializeAdd(action, null, -1);
}
else
{
if (changedItems == null)
{
throw new ArgumentNullException(nameof(changedItems));
}
if (startingIndex < -1)
{
throw new ArgumentException(SR.IndexCannotBeNegative, nameof(startingIndex));
}
InitializeAddOrRemove(action, changedItems, startingIndex);
}
}
/// <summary>
/// Construct a NotifyChangeRequestedEventArgs that describes a multi-item change.
/// </summary>
/// <param name="action">The action that caused the event.</param>
/// <param name="changedItems">The items affected by the change.</param>
public NotifyChangeRequestedEventArgs(NotifyChangeRequestedAction action, IList <T> changedItems)
{
if ((action != NotifyChangeRequestedAction.Add) && (action != NotifyChangeRequestedAction.Remove) &&
(action != NotifyChangeRequestedAction.Reset))
{
throw new ArgumentException(SR.MustBeResetAddOrRemoveActionForCtor, nameof(action));
}
if (action == NotifyChangeRequestedAction.Reset)
{
if (changedItems != null)
{
throw new ArgumentException(SR.ResetActionRequiresNullItem, nameof(action));
}
InitializeAdd(action, null, -1);
}
else
{
if (changedItems == null)
{
throw new ArgumentNullException(nameof(changedItems));
}
InitializeAddOrRemove(action, changedItems, -1);
}
}
/// <summary>
/// Construct a NotifyChangeRequestedEventArgs with given fields (no validation). Used by WinRT marshaling.
/// </summary>
internal NotifyChangeRequestedEventArgs(NotifyChangeRequestedAction action, IList <T> newItems, IList <T> oldItems, int newIndex, int oldIndex)
{
_action = action;
_newItems = (newItems == null) ? null : new ReadOnlyList <T>(newItems);
_oldItems = (oldItems == null) ? null : new ReadOnlyList <T>(oldItems);
_newStartingIndex = newIndex;
_oldStartingIndex = oldIndex;
}
/// <summary>
/// Construct a NotifyChangeRequestedEventArgs that describes a reset change.
/// </summary>
/// <param name="action">The action that caused the event (must be Reset).</param>
public NotifyChangeRequestedEventArgs(NotifyChangeRequestedAction action)
{
if (action != NotifyChangeRequestedAction.Reset)
{
throw new ArgumentException(string.Format(SR.WrongActionForCtor, NotifyChangeRequestedAction.Reset), nameof(action));
}
InitializeAdd(action, null, -1);
}
/// <summary>
/// Construct a NotifyChangeRequestedEventArgs that describes a one-item Replace event.
/// </summary>
/// <param name="action">Can only be a Replace action.</param>
/// <param name="newItem">The new item replacing the original item.</param>
/// <param name="oldItem">The original item that is replaced.</param>
/// <param name="index">The index of the item being replaced.</param>
public NotifyChangeRequestedEventArgs(NotifyChangeRequestedAction action, T newItem, T oldItem, int index)
{
if (action != NotifyChangeRequestedAction.Replace)
{
throw new ArgumentException(string.Format(SR.WrongActionForCtor, NotifyChangeRequestedAction.Replace), nameof(action));
}
InitializeMoveOrReplace(action, new T[] { newItem }, new T[] { oldItem }, index, index);
}
private void InitializeAddOrRemove(NotifyChangeRequestedAction action, IList <T> changedItems, int startingIndex)
{
if (action == NotifyChangeRequestedAction.Add)
{
InitializeAdd(action, changedItems, startingIndex);
}
else
{
Debug.Assert(action == NotifyChangeRequestedAction.Remove, $"Unsupported action: {action}");
InitializeRemove(action, changedItems, startingIndex);
}
}
/// <summary>
/// Construct a NotifyChangeRequestedEventArgs that describes a multi-item Move event.
/// </summary>
/// <param name="action">The action that caused the event.</param>
/// <param name="changedItems">The items affected by the change.</param>
/// <param name="index">The new index for the changed items.</param>
/// <param name="oldIndex">The old index for the changed items.</param>
public NotifyChangeRequestedEventArgs(NotifyChangeRequestedAction action, IList <T> changedItems, int index, int oldIndex)
{
if (action != NotifyChangeRequestedAction.Move)
{
throw new ArgumentException(string.Format(SR.WrongActionForCtor, NotifyChangeRequestedAction.Move), nameof(action));
}
if (index < 0)
{
throw new ArgumentException(SR.IndexCannotBeNegative, nameof(index));
}
InitializeMoveOrReplace(action, changedItems, changedItems, index, oldIndex);
}
/// <summary>
/// Construct a NotifyChangeRequestedEventArgs that describes a multi-item Replace event.
/// </summary>
/// <param name="action">Can only be a Replace action.</param>
/// <param name="newItems">The new items replacing the original items.</param>
/// <param name="oldItems">The original items that are replaced.</param>
/// <param name="startingIndex">The starting index of the items being replaced.</param>
public NotifyChangeRequestedEventArgs(NotifyChangeRequestedAction action, IList <T> newItems, IList <T> oldItems, int startingIndex)
{
if (action != NotifyChangeRequestedAction.Replace)
{
throw new ArgumentException(string.Format(SR.WrongActionForCtor, NotifyChangeRequestedAction.Replace), nameof(action));
}
if (newItems == null)
{
throw new ArgumentNullException(nameof(newItems));
}
if (oldItems == null)
{
throw new ArgumentNullException(nameof(oldItems));
}
InitializeMoveOrReplace(action, newItems, oldItems, startingIndex, startingIndex);
}
private void InitializeMoveOrReplace(NotifyChangeRequestedAction action, IList <T> newItems, IList <T> oldItems, int startingIndex, int oldStartingIndex)
{
InitializeAdd(action, newItems, startingIndex);
InitializeRemove(action, oldItems, oldStartingIndex);
}
private void InitializeRemove(NotifyChangeRequestedAction action, IList <T> oldItems, int oldStartingIndex)
{
_action = action;
_oldItems = (oldItems == null) ? null : new ReadOnlyList <T>(oldItems);
_oldStartingIndex = oldStartingIndex;
}
private void InitializeAdd(NotifyChangeRequestedAction action, IList <T> newItems, int newStartingIndex)
{
_action = action;
_newItems = (newItems == null) ? null : new ReadOnlyList <T>(newItems);
_newStartingIndex = newStartingIndex;
}
