sqlsitemapprovider.cs

C#语言制作asp.net网上商店的

using System;
using System.Web;
using System.Data.SqlClient;
using System.Collections.Specialized;
using System.Configuration;
using System.Web.Configuration;
using System.Collections.Generic;
using System.Configuration.Provider;
using System.Security.Permissions;
using System.Data.Common;
using System.Data;
using System.Web.Caching;
namespace NetShopForge.Provider
{ 
/// <summary>
/// Summary description for SqlSiteMapProvider
/// </summary>
[SqlClientPermission(SecurityAction.Demand, Unrestricted = true)]
public class SqlSiteMapProvider : StaticSiteMapProvider
{
    private const string _errmsg1 = "Missing node ID";
    private const string _errmsg2 = "Duplicate node ID";
    private const string _errmsg3 = "Missing parent ID";
    private const string _errmsg4 = "Invalid parent ID";
    private const string _errmsg5 = "Empty or missing connectionStringName";
    private const string _errmsg6 = "Missing connection string";
    private const string _errmsg7 = "Empty connection string";
    private const string _errmsg8 = "Invalid sqlCacheDependency";
    private const string _cacheDependencyName = "__SiteMapCacheDependency";

    private string _connect;              // Database connection string
    private string _database, _table;     // Database info for SQL Server 7/2000 cache dependency
    private bool _2005dependency = false; // Database info for SQL Server 2005 cache dependency
    private int _indexID, _indexTitle, _indexUrl, _indexDesc, _indexRoles, _indexParent;
    private Dictionary<int, SiteMapNode> _nodes = new Dictionary<int, SiteMapNode>(16);
    private readonly object _lock = new object();
    private SiteMapNode _root;

    public override void Initialize(string name, NameValueCollection config)
    {
        // Verify that config isn't null
        if (config == null)
            throw new ArgumentNullException("config");

        // Assign the provider a default name if it doesn't have one
        if (String.IsNullOrEmpty(name))
            name = "SqlSiteMapProvider";

        // Add a default "description" attribute to config if the
        // attribute doesn抰 exist or is empty
        if (string.IsNullOrEmpty(config["description"]))
        {
            config.Remove("description");
            config.Add("description", "SQL site map provider");
        }

        // Call the base class's Initialize method
        base.Initialize(name, config);

        // Initialize _connect
        string connect = config["connectionStringName"];

        if (String.IsNullOrEmpty(connect))
            throw new ProviderException(_errmsg5);

        config.Remove("connectionStringName");

        if (WebConfigurationManager.ConnectionStrings[connect] == null)
            throw new ProviderException(_errmsg6);

        _connect = WebConfigurationManager.ConnectionStrings[connect].ConnectionString;

        if (String.IsNullOrEmpty(_connect))
            throw new ProviderException(_errmsg7);

        // Initialize SQL cache dependency info
        string dependency = config["sqlCacheDependency"];

        if (!String.IsNullOrEmpty(dependency))
        {
            if (String.Equals(dependency, "CommandNotification", StringComparison.InvariantCultureIgnoreCase))
            {
                SqlDependency.Start(_connect);
                _2005dependency = true;
            }
            else
            {
                // If not "CommandNotification", then extract database and table names
                string[] info = dependency.Split(new char[] { ':' });
                if (info.Length != 2)
                    throw new ProviderException(_errmsg8);

                _database = info[0];
                _table = info[1];
            }

            config.Remove("sqlCacheDependency");
        }

        // SiteMapProvider processes the securityTrimmingEnabled
        // attribute but fails to remove it. Remove it now so we can
        // check for unrecognized configuration attributes.

        if (config["securityTrimmingEnabled"] != null)
            config.Remove("securityTrimmingEnabled");

        // Throw an exception if unrecognized attributes remain
        if (config.Count > 0)
        {
            string attr = config.GetKey(0);
            if (!String.IsNullOrEmpty(attr))
                throw new ProviderException("Unrecognized attribute: " + attr);
        }
    }

    public override SiteMapNode BuildSiteMap()
    {
        lock (_lock)
        {
            // Return immediately if this method has been called before
            if (_root != null)
                return _root;

            // Query the database for site map nodes
            SqlConnection connection = new SqlConnection(_connect);

            try
            {
                SqlCommand command = new SqlCommand("nsf_SiteMap_GetSiteMap", connection);
                command.CommandType = CommandType.StoredProcedure;

                // Create a SQL cache dependency if requested
                SqlCacheDependency dependency = null;

                if (_2005dependency)
                    dependency = new SqlCacheDependency(command);
                else if (!String.IsNullOrEmpty(_database) && !string.IsNullOrEmpty(_table))
                    dependency = new SqlCacheDependency(_database, _table);

                connection.Open();
                SqlDataReader reader = command.ExecuteReader();
                _indexID = reader.GetOrdinal("ID");
                _indexUrl = reader.GetOrdinal("Url");
                _indexTitle = reader.GetOrdinal("Title");
                _indexDesc = reader.GetOrdinal("Description");
                _indexRoles = reader.GetOrdinal("Roles");
                _indexParent = reader.GetOrdinal("Parent");

                if (reader.Read())
                {
                    // Create the root SiteMapNode and add it to the site map
                    _root = CreateSiteMapNodeFromDataReader(reader);
                    AddNode(_root, null);

                    // Build a tree of SiteMapNodes underneath the root node
                    while (reader.Read())
                    {
                        // Create another site map node and add it to the site map
                        SiteMapNode node = CreateSiteMapNodeFromDataReader(reader);
                        AddNode(node, GetParentNodeFromDataReader(reader));
                    }

                    // Use the SQL cache dependency
                    if (dependency != null)
                    {
                        HttpRuntime.Cache.Insert(_cacheDependencyName, new object(), dependency,
                            Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration, CacheItemPriority.NotRemovable,
                            new CacheItemRemovedCallback(OnSiteMapChanged));
                    }
                }
            }
            finally
            {
                connection.Close();
            }

            // Return the root SiteMapNode
            return _root;
        }
    }

    protected override SiteMapNode GetRootNodeCore()
    {
        lock (_lock)
        {
            BuildSiteMap();
            return _root;
        }
    }

    // Helper methods
    private SiteMapNode CreateSiteMapNodeFromDataReader(DbDataReader reader)
    {
        // Make sure the node ID is present
        if (reader.IsDBNull(_indexID))
            throw new ProviderException(_errmsg1);

        // Get the node ID from the DataReader
        int id = reader.GetInt32(_indexID);

        // Make sure the node ID is unique
        if (_nodes.ContainsKey(id))
            throw new ProviderException(_errmsg2);

        // Get title, URL, description, and roles from the DataReader
        string title = reader.IsDBNull(_indexTitle) ? null : reader.GetString(_indexTitle).Trim();
        string url = reader.IsDBNull(_indexUrl) ? null : reader.GetString(_indexUrl).Trim();
        string description = reader.IsDBNull(_indexDesc) ? null : reader.GetString(_indexDesc).Trim();
        string roles = reader.IsDBNull(_indexRoles) ? null : reader.GetString(_indexRoles).Trim();

        // If roles were specified, turn the list into a string array
        string[] rolelist = null;
        if (!String.IsNullOrEmpty(roles))
            rolelist = roles.Split(new char[] { ',', ';' }, 512);

        // Create a SiteMapNode
        SiteMapNode node = new SiteMapNode(this, id.ToString(), url, title, description, rolelist, null, null, null);

        // Record the node in the _nodes dictionary
        _nodes.Add(id, node);

        // Return the node        
        return node;
    }

    private SiteMapNode GetParentNodeFromDataReader(DbDataReader reader)
    {
        // Make sure the parent ID is present
        if (reader.IsDBNull(_indexParent))
            throw new ProviderException(_errmsg3);

        // Get the parent ID from the DataReader
        int pid = reader.GetInt32(_indexParent);

        // Make sure the parent ID is valid
        if (!_nodes.ContainsKey(pid))
            throw new ProviderException(_errmsg4);

        // Return the parent SiteMapNode
        return _nodes[pid];
    }

    void OnSiteMapChanged(string key, object item, CacheItemRemovedReason reason)
    {
        lock (_lock)
        {
            if (key == _cacheDependencyName && reason == CacheItemRemovedReason.DependencyChanged)
            {
                // Refresh the site map
                Clear();
                _nodes.Clear();
                _root = null;
            }
        }
    }
}
}