说起那个无限级分类，相信很多人都知道是什么东西，也曾经做过。我也相信，大家用得最多的实现方式就是做一个递归。最近我也要做一个带无限级分类的菜单，但是我又不想用递归来做，所以我需要用其他方式来实现，那就是迭代了。
首先，我需要定义一个实体模型，这举一个省市无限级的例子：
class Loaction
{
public int ID { get; set; }
public int PID { get; set; }
public string Name { get; set; } //地方名
public int Level { get; set; } //深度
}
然后写方法，这里需要利用到栈的后进先出的特点：
public static List<Loaction> Soft(List<Loaction> data, int pid)
{
Stack task = new Stack();
task.Push(pid);
List<Loaction> tree = new List<Loaction>();
int level = 0;
while (task.Count > 0)
{
bool flag = false;
for (int i = 0; i < data.Count; i++)
{
var l = data[i];
if (l.PID == pid)
{
pid = l.ID;
task.Push(l.ID);
l.Level = level;
level++;
tree.Add(l);
data.Remove(l);
i--;
flag=true;
}
}
if (!flag)
{
task.Pop();
if (task.Count > 0)
{
pid = Convert.ToInt32(task.Peek());
level--;
}
}
}
return tree;
}
最后准备数据->调用->输出：然后效果如下：
static void Main(string[] args)
{
var data = new List<Loaction>();
data.Add(new Loaction() { ID = 1, PID = 0, Name = "北京" });
data.Add(new Loaction() { ID = 2, PID = 0, Name = "广东" });
data.Add(new Loaction() { ID = 3, PID = 0, Name = "上海" });
data.Add(new Loaction() { ID = 4, PID = 0, Name = "重庆" });
data.Add(new Loaction() { ID = 5, PID = 0, Name = "黑龙江" });
data.Add(new Loaction() { ID = 6, PID = 1, Name = "丰台" });
data.Add(new Loaction() { ID = 7, PID = 1, Name = "海淀" });
data.Add(new Loaction() { ID = 8, PID = 1, Name = "石景山" });
data.Add(new Loaction() { ID = 9, PID = 3, Name = "上海市" });
data.Add(new Loaction() { ID = 10, PID = 2, Name = "广州" });
data.Add(new Loaction() { ID = 11, PID = 5, Name = "齐齐哈尔" });
data.Add(new Loaction() { ID = 12, PID = 2, Name = "茂名" });
data.Add(new Loaction() { ID = 13, PID = 2, Name = "深圳" });
data.Add(new Loaction() { ID = 14, PID = 5, Name = "哈尔滨" });
data.Add(new Loaction() { ID = 15, PID = 4, Name = "重庆市" });
data.Add(new Loaction() { ID = 16, PID = 2, Name = "东莞" });
data.Add(new Loaction() { ID = 17, PID = 2, Name = "中山" });
data.Add(new Loaction() { ID = 18, PID = 16, Name = "厚街镇" });
var tree = Soft(data, 0);
foreach (var t in tree)
{
var sb = new StringBuilder();
for (int i = 0; i < t.Level; i++)
{
sb.Append(" ");
}
sb.Append(t.Name);
Console.WriteLine(sb.ToString());
}
Console.ReadKey();
}
就是这个样子。。。。。(END)
