Question

我们说我有一个班级：

public class User{
    public string Name {get;set;}
    public int SeqNumber {get;set;}
}

public List<User> UserClass {get;set;}

对于动态示例，我有10个用户。每个SeqNumber都是唯一的，从1到10，基于用户数量。 SeqNumber将用于按升序对用户进行排序。但是，SeqNumber必须是唯一的，并且仍在用户数量的范围内。

UserClass = new List<User>() {
     new User({Name = "Rose", SeqNumber = 1}),
     new User({Name = "Ryu", SeqNumber = 2}),
     new User({Name = "Sagat", SeqNumber = 3}),
     new User({Name = "Dhalsim", SeqNumber = 4}),
     new User({Name = "Zangief", SeqNumber = 5}),
     new User({Name = "Ken", SeqNumber = 6}),
     new User({Name = "Chun-Li", SeqNumber = 7}),
     new User({Name = "Vega", SeqNumber = 8}),
     new User({Name = "Balrog", SeqNumber = 9}),
     new User({Name = "M. Bison", SeqNumber = 10}),
};

让我们说有人决定将Ryu的SeqNumber更改为6，作为使用示例。 Sagat将升至2，Dhalsim将升至3，Zangief将升至4，Ken将升至5。反过来，如果我将M.Bison的SeqNumber移动到2怎么办？其他用户的SeqNumber应该增加1.如何实现？

Answer 1

您可以使用以下扩展方法来执行此操作，该方法在列表中使用索引器：

public static void MoveAndRecalculateSequence(
    this IList<User> users, int moveFromIndex, int moveToIndex)
{
    // Capture a reference to the user we want to move.
    var user = users[moveFromIndex];

    // Remove it from the list at it's current index.
    users.RemoveAt(moveFromIndex);

    // Insert the user at the required destination.
    users.Insert(moveToIndex, user);

    // Recalculate the seq number using the index of the list.
    for(int i = 0; i < users.length; i++)
    {
        users[i].SeqNumber = i + 1;
    }
}

并按原样使用：

// remember indexes start at 0 in C#
users.MoveAndRecalculateSequence(1, 5);

Answer 2

将您的用户放入列表中，以便您可以动态访问它们：

UserClass = new List<User>() {
  new User({Name = "xxxx", SeqNumber = 1}),
  new User({Name = "xxxx", SeqNumber = 2}),
  new User({Name = "xxxx", SeqNumber = 3}),
  ...
};

现在，您可以获取应更改SeqNumber属性的用户，即数字为2到6的用户，并为其设置新值：

UserClass
  .Where(u => u.SeqNumber => 2 && u.SeqNumber <= 6)
  .ToList()
  .ForEach(u => {
    if (u.SeqNumber == 2) {
      u.SeqNumber = 6
    } else {
      u.SeqNumber--;
    }
  });

序列号序列，没有从类重复

2 个答案: