Binding ASP.Net Menu Control to a Collection

问题:

i am trying to use this code to bind my asp.net menu control to a collection.. but its giving me an error that my collection is now IHierarchyEnumerable.. which I understand why too..

    StringCollection sc = pos.getAllmembers();
    Menu1.DataSource = pos.getAllmembers().GetEnumerator();

is there a way around this..

回答1:

The menu control requires a collection of IHierarcyData objects in a collection that implements IHierarchicalEnumerable.

Start with a IHierarcyData class that will store each string from the StringCollection...

public class MyMenuItem : IHierarchyData
{
    public MyMenuItem(string s)
    {
        Item = s;
    }

    public override string ToString()
    {
        return Item.ToString();
    }

    #region IHierarchyData Members

    public IHierarchicalEnumerable GetChildren()
    {
        return null;
    }

    public IHierarchyData GetParent()
    {
        return null;
    }

    public bool HasChildren
    {
        get { return false; }
    }

    public object Item
    {
        get; set;
    }

    public string Path
    {
        get { return string.Empty; }
    }

    public string Type
    {
        get { return string.Empty; }
    }

    #endregion
}

Build a class that will be the collection...

public class MyMenu : StringCollection, IHierarchicalEnumerable
{
    List<IHierarchyData> _list = new List<IHierarchyData>();

    public void Add(StringCollection strings)
    {
        foreach (string s in strings)
        {
            MyMenuItem i = new MyMenuItem(s);
            _list.Add(i);
        }
    }

    #region IHierarchicalEnumerable Members

    public IHierarchyData GetHierarchyData(object enumeratedItem)
    {
        return enumeratedItem as IHierarchyData;
    }

    #endregion

    #region IEnumerable Members

    public System.Collections.IEnumerator GetEnumerator()
    {
        return _list.GetEnumerator();
    }

    #endregion
}

In the page you can now construct the menu...

 MyMenu pos = new MyMenu();

 StringCollection sc = new StringCollection();
 sc.Add("First");
 sc.Add("Second");
 pos.Add(sc);

 Menu1.DataSource = pos;
 Menu1.DataBind();

回答2:

You can try writting a wrapper like in this msdn article:

http://msdn.microsoft.com/en-us/library/system.web.ui.ihierarchicalenumerable.aspx

public class StringHeirarchy : StringCollection,IHierarchyEnumerable
{
   public IHierarchyData GetHierarchyData(object enumeratedItem) 
   {
        return enumeratedItem as IHierarchyData; 
   } 
}