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创建匿名类型的堆栈

anonymous-types .net c#

4

user410989 · 技术社区 · 14 年前

 class Foo
 {
  public int id{get;set;}
  public IEnumerable<Foo> Childs;
       //some other properties
 }

现在我想在Foo对象及其所有子对象上处理一些业务逻辑,如下所示:

 public void DoSomeWorkWith(Foo x)
 {
  var firstItem = new {level = 0, item = x};
  var s = new Stack<?>(?); //What type to use?
  s.Push(firstItem);
  while(s.Any())
  {
    var current = s.Pop();
    DoSomeBusiness(current.item);
    DoSomeMoreBusiness(current.item);
    Log(current.level, current.item.id);
    foreach(Foo child in current.item.Childs)
       s.Push(new {level = current.level + 1, item = child});
   }
}

我需要跟踪孩子们的(相对)水平/深度。 Stack<T> 匿名类型?当然,我可以创建一个简单的类,而不是匿名类型(或者更复杂的递归函数),但是如何在没有额外类的情况下解决这个问题呢?

4 回复 | 直到 14 年前

1

sloth JohnnBlade 14 年前

你可以把它放到这样一个方法中:

public Stack<T> CreateStackWithInitialItem<T>(T initialItem)
{
    var s = new Stack<T>();
    s.Push(initialItem);
    return s;
}

public void DoSomeWorkWith(Foo x)
{
    var s = CreateStackWithInitialItem(new {level = 0, item = x});
    while(s.Any())
    {
        ...
    }
}

2

7

Marc Gravell 14 年前

怎么样:

public static Stack<T> CreateEmptyStack<T>(T template) {
    return new Stack<T>();
}
...
var stack = CreateEmptyStack(firstItem);

它使用泛型类型推断来处理 T .

3

1

Roland Sommer 14 年前

使用元组怎么样( System.Tuple<> )而不是匿名类型?

public void DoSomeWorkWith(Foo x)
{
    var firstItem = new Tuple<int, Foo>(0, x);
    var s = new Stack<Tuple<int, Foo>>();
    s.Push(firstItem);
    while (s.Any())
    {
        var current = s.Pop();
        DoSomeBusiness(current.Item2);
        DoSomeMoreBusiness(current.Item2);
        Log(current.Item1, current.Item2.id);
        foreach (Foo child in current.Item2.Childs)
            s.Push(new Tuple<int, Foo>(current.Item1 + 1, child));
    }
}

System.Dynamic.ExpandoObject .

public void DoSomeWorkWith(Foo x)
{
    dynamic firstItem = new ExpandoObject();
    firstItem.level = 1;
    firstItem.item = x;

    var s = new Stack<dynamic>();
    s.Push(firstItem);
    while (s.Any())
    {
        var current = s.Pop();
        DoSomeBusiness(current.item);
        DoSomeMoreBusiness(current.item);
        Log(current.level, current.item.id);
        foreach (Foo child in current.item.Childs)
        {
            dynamic next = new ExpandoObject();
            next.level = current.level + 1;
            next.item = child;
            s.Push(next);
        }
    }
}

4

0

Jacob 14 年前

// (If you're not using C# 4, you can replace the default level with a function
// overload or just remove the default value)

void ProcessFooRecursive(Foo foo, int level = 0) 
{
    DoSomeBusiness(foo);
    DoSomeMoreBusiness(foo);
    Log(level, foo.id);

    var newDepth = level + 1;
    foreach (var child in foo.Childs)
    {
        ProcessFooRecursive(child, newDepth);
    }
}