基于这些人的工作:
- http://dvanderboom.wordpress.com/2008/03/15/treet-implementing-a-non-binary-tree-in-c/
- http://www.matthidinger.com/archive/2009/02/08/asp.net-mvc-recursive-treeview-helper.aspx
我正在尝试实现一个 TreeView 助手,它可以这样使用:
<%= Html.TreeView("records",
Library.Instance.Records,
r => r.Children,
r => r.ID) %>
树结构定义如下:
public class Tree<T> : TreeNode<T> where T : TreeNode<T>
{ }
public class TreeNode<T> : IDisposable where T : TreeNode<T>
{
public T Parent { get; set; }
public TreeNodeList<T> Children { get; set; }
}
public class TreeNodeList<T> : List<TreeNode<T>> where T : TreeNode<T>
{
public T Parent;
public T Add(T node)
{
base.Add(node);
node.Parent = (T)Parent;
return node;
}
public void Remove(T node)
{
if (node != null)
node.Parent = null;
base.Remove(node);
}
}
TreeView 助手有这个签名:
public static string TreeView<T>(this HtmlHelper htmlHelper, string treeId,
IEnumerable<T> rootItems, Func<T, IEnumerable<T>> childrenProperty,
Func<T, string> itemContent, bool includeJavascript, string emptyContent)
{
...
}
因此,我需要我的树结构来实现 IEnumerable,这样我就可以将它与 TreeView 助手一起使用,这就引出了一个问题:在这种情况下,我应该在哪里以及如何实现 IEnumerable?
最佳答案
我不完全理解您的树结构的确切细节,但这是一个简单的实现,它采用通用节点树并将其递归呈现为 html 列表。
public static string TreeView<T>(IEnumerable<T> rootItems,
Func<T, IEnumerable<T>> childrenProperty,
Func<T, string> itemContent)
{
if (rootItems == null || !rootItems.Any()) return null;
var builder = new StringBuilder();
builder.AppendLine("<ul>");
foreach (var item in rootItems)
{
builder.Append(" <li>").Append(itemContent(item)).AppendLine("</li>");
var childContent = htmlHelper.TreeView(treeId,
childrenProperty(item),
childrenProperty,
itemContent);
if (childContent != null)
{
var indented = childContent.Replace(Environment.NewLine,
Environment.NewLine + " ");
builder.Append(" ").AppendLine(indented);
}
}
builder.Append("</ul>");
return builder.ToString();
}
我使用的节点类相对简单,只有两个属性。
public class Node<T>
{
public Node(T data)
{
Data = data;
Children = new List<Node<T>>();
}
public T Data { get; private set; }
public ICollection<Node<T>> Children { get; private set; }
}
下面是一些将树输出到控制台的测试代码。
var Records = new[] {
new Node<string>("one") {
Children = {
new Node<string>("one-one") {
Children = {
new Node<string>("one-one-one"),
new Node<string>("one-one-two"),
new Node<string>("one-one-three")
}
},
new Node<string>("one-two"),
new Node<string>("one-three")
}
},
new Node<string>("two"),
new Node<string>("three")
};
Console.WriteLine(TreeView(Records,
r => r.Children,
r => r.Data));
下面是上述代码的结果。
<ul>
<li>one</li>
<ul>
<li>one-one</li>
<ul>
<li>one-one-one</li>
<li>one-one-two</li>
<li>one-one-three</li>
</ul>
<li>one-two</li>
<li>one-three</li>
</ul>
<li>two</li>
<li>three</li>
</ul>
关于c# - 在树结构上实现 IEnumerable,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/1928643/