偶也不是完全清楚，慢慢讲吧：
Menu控件可以绑定SiteMapDataSource和XmlDataSource
先说SiteMapDataSource,他默认通过SiteMapProvider读取站点根目录下Web.sitemap作为数据源，或者，可以实现自己的站点地图提供程序，通过修改SiteMapDataSouce的SiteMapProvider属性使用自定义的提供程序。
创建自定义站点地图提供程序的三个主要理由如下：
1。为了将站点地图信息存储在 ASP.NET 默认站点地图提供程序不支持的数据源中。例如，您可能希望将站点地图数据存储在 Visual FoxPro 数据库、Oracle 数据库或其他数据源中。
2。为了使用与 Web.sitemap 文件所使用的架构不同的架构来管理导航信息。例如，您可能拥有一个用于存储站点地图数据的现有实现。
3。为了使用动态站点地图结构。例如，您可能希望每个客户端帐户能够查看不同的站点地图。
演示一个完整的基于 Access 的站点地图提供程序：
namespace Samples.AspNet.CS.Controls {
using System;
using System.Collections;
using System.Collections.Specialized;
using System.Data;
using System.Data.OleDb;
using System.Security.Permissions;
using System.Web;
/// An extremely simple AccessSiteMapProvider that only supports a
/// site map node hierarchy 1 level deep.
[AspNetHostingPermission(SecurityAction.Demand, Level=AspNetHostingPermissionLevel.Minimal)]
public class AccessSiteMapProvider : StaticSiteMapProvider
{
private SiteMapNode rootNode = null;
private OleDbConnection accessConnection = null;
// This string is case sensitive.
private string AccessConnectionStringName = "accessSiteMapConnectionString";
// Implement a default constructor.
public AccessSiteMapProvider () { }
// Some basic state to help track the initialization state of the provider.
private bool initialized = false;
public virtual bool IsInitialized {
get {
return initialized;
}
}
// Return the root node of the current site map.
public override SiteMapNode RootNode {
get {
SiteMapNode temp = null;
temp = BuildSiteMap();
return temp;
}
}
protected override SiteMapNode GetRootNodeCore() {
return RootNode;
}
// Initialize is used to initialize the properties and any state that the
// AccessProvider holds, but is not used to build the site map.
// The site map is built when the BuildSiteMap method is called.
public override void Initialize(string name, NameValueCollection attributes) {
if (IsInitialized)
return;
base.Initialize(name, attributes);
// Create and test the connection to the Microsoft Access database.
// Retrieve the Value of the Access connection string from the
// attributes NameValueCollection.
string connectionString = attributes[AccessConnectionStringName];
if (null == connectionString || connectionString.Length == 0)
throw new Exception ("The connection string was not found.");
else
accessConnection = new OleDbConnection(connectionString);
initialized = true;
}
///
/// SiteMapProvider and StaticSiteMapProvider methods that this derived class must override.
///
// Clean up any collections or other state that an instance of this may hold.
protected override void Clear() {
lock (this) {
rootNode = null;
base.Clear();
}
}
// Build an in-memory representation from persistent
// storage, and return the root node of the site map.
public override SiteMapNode BuildSiteMap() {
// Since the SiteMap class is static, make sure that it is
// not modified while the site map is built.
lock(this) {
// If there is no initialization, this method is being
// called out of order.
if (! IsInitialized) {
throw new Exception("BuildSiteMap called incorrectly.");
}
// If there is no root node, then there is no site map.
if (null == rootNode) {
// Start with a clean slate
Clear();
// Select the root node of the site map from Microsoft Access.
int rootNodeId = -1;
if (accessConnection.State == ConnectionState.Closed)
accessConnection.Open();
OleDbCommand rootNodeCommand =
new OleDbCommand("SELECT nodeid, url, name FROM SiteMap WHERE parentnodeid IS NULL",
accessConnection);
OleDbDataReader rootNodeReader = rootNodeCommand.ExecuteReader();
if(rootNodeReader.HasRows) {
rootNodeReader.Read();
rootNodeId = rootNodeReader.GetInt32(0);
// Create a SiteMapNode that references the current StaticSiteMapProvider.
rootNode = new SiteMapNode(this,
rootNodeId.ToString(),
rootNodeReader.GetString(1),
rootNodeReader.GetString(2));
}
else return null;
rootNodeReader.Close();
// Select the child nodes of the root node.
OleDbCommand childNodesCommand =
new OleDbCommand("SELECT nodeid, url, name FROM SiteMap WHERE parentnodeid = ?",
accessConnection);
OleDbParameter rootParam = new OleDbParameter("parentid", OleDbType.Integer);
rootParam.Value = rootNodeId;
childNodesCommand.Parameters.Add(rootParam);
OleDbDataReader childNodesReader = childNodesCommand.ExecuteReader();
if (childNodesReader.HasRows) {
SiteMapNode childNode = null;
while(childNodesReader.Read()) {
childNode = new SiteMapNode(this,
childNodesReader.GetInt32(0).ToString(),
childNodesReader.GetString(1),
childNodesReader.GetString(2));
// Use the SiteMapNode AddNode method to add
// the SiteMapNode to the ChildNodes collection.
AddNode(childNode, rootNode);
}
}
childNodesReader.Close();
accessConnection.Close();
}
return rootNode;
}
}
}
}
