public void UpdateOrder_MoveDown_SameItem()
{
var items = GenerateList();
var dropInfo = new MudItemDropInfo <ItemsWithOrder>(items[3], "something", 3);
items.UpdateOrder(dropInfo, x => x.Prio);
var expectedOrders = new[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
var actualOrders = items.Select(x => x.Prio).ToList();
actualOrders.Should().ContainInOrder(expectedOrders);
}
public void UpdateOrder_MoveUp_EdgeCase()
{
var items = GenerateList();
//move item item-5 to index 0
var dropInfo = new MudItemDropInfo <ItemsWithOrder>(items[9], "something", 0);
items.UpdateOrder(dropInfo, x => x.Prio);
var expectedOrders = new[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 };
var actualOrders = items.Select(x => x.Prio).ToList();
actualOrders.Should().ContainInOrder(expectedOrders);
}
public static void UpdateOrder <T>(this IEnumerable <T> items, MudItemDropInfo <T> dropInfo, Expression <Func <T, int> > valueUpdater, int zoneOffset = 0)
{
var memberSelectorExpression = valueUpdater.Body as MemberExpression;
if (memberSelectorExpression == null)
{
throw new InvalidOperationException();
}
var property = memberSelectorExpression.Member as PropertyInfo;
if (property == null)
{
throw new InvalidOperationException();
}
var newIndex = dropInfo.IndexInZone + zoneOffset;
var item = dropInfo.Item;
int index = 0;
foreach (var _item in items.OrderBy(x => (int)property.GetValue(x)))
{
if (_item.Equals(item) == true)
{
property.SetValue(item, newIndex);
}
else
{
if (index == newIndex)
{
index++;
}
property.SetValue(_item, index);
index++;
}
}
}