Example Access Site-Map Provider

Illustrates a complete Access-based site-map provider.

Example

The following code example demonstrates how you can extend the StaticSiteMapProvider class to use Microsoft Access as a site-map provider. The site-map provider uses the .NET Framework Data Provider for OLE DB to connect to the Access database.

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;
            }
        }
    }
}

package Samples.AspNet.JSL;
import System.*;
import System.Collections.*;
import System.Collections.Specialized.*;
import System.Data.*;
import System.Data.OleDb.*;
import System.Web.*;
import System.Configuration.*;

/// An extremely simple AccessSiteMapProvider that only supports a
/// site map node hierarchy 1 level deep.
public class AccessSiteMapProvider extends StaticSiteMapProvider
{
	private SiteMapNode rootNode = null;
	private OleDbConnection accessConnection = null;

	// This string is case sensitive.
	public String accessConnectionStringName = "accessSiteMapConnectionString";

	// Implement a default constructor.
	public AccessSiteMapProvider()
	{
	} //AccessSiteMapProvider 

	// Some basic state to help track the initialization state of the provider.
	private boolean initialized = false;

	/** @property 
	 */
	public boolean get_IsInitialized()
	{
		return initialized;
	} //get_IsInitized.

	// Return the root node of the current site map.
	/** @property 
	 */
	public SiteMapNode get_RootNode() throws Exception
	{
		SiteMapNode temp = null;
		temp = BuildSiteMap();
		return temp;
	} //get_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 void Initialize(String name, NameValueCollection attributes) 
        throws Exception
	{
		if (get_IsInitialized())
		{
			return;
		}

		super.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.get_Item(
			accessConnectionStringName);

		if (null == connectionString || connectionString.get_Length() == 0)
		{
			throw new Exception("The connection string was not found.");
		}
		else
		{
			accessConnection = new OleDbConnection(connectionString);
		}
		initialized = true;
	} //Initialize

	///
	/// 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 void Clear()
	{
		synchronized (this)
		{
			rootNode = null;
			super.Clear();
		}
	} //Clear

	// Build an in-memory representation from persistent
	// storage, and return the root node of the site map.
	public SiteMapNode BuildSiteMap() throws Exception
	{
		// Since the SiteMap class is static, make sure that it is
		// not modified while the site map is built.
		synchronized (this)
		{
			// If there is no initialization, this method is being
			// called out of order.
			if (!get_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.get_State().Equals(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.get_HasRows())
				{
					rootNodeReader.Read();
					rootNodeId = rootNodeReader.GetInt32(0);
					// Create a SiteMapNode that references the current 
					// StaticSiteMapProvider.
					rootNode = new SiteMapNode(this,
						((Int32)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.set_Value((Int32)rootNodeId);
				childNodesCommand.get_Parameters().Add(rootParam);

				OleDbDataReader childNodesReader = childNodesCommand.
					ExecuteReader();

				if (childNodesReader.get_HasRows())
				{
					SiteMapNode childNode = null;
					while (childNodesReader.Read())
					{
						childNode = new SiteMapNode(this,
							Convert.ToString(childNodesReader.GetInt32(0)), 
							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;
		}
	} //BuildSiteMap

	protected SiteMapNode GetRootNodeCore()
	{
		return null;
	} //GetRootNodeCore
} //AccessSiteMapProvider 

To create the Access table that is used by the previous code example as the site-map data store, issue the following data-definition query in a new or existing Access database, and then save the Access database with the file name Sitemap.mdb.

CREATE TABLE SiteMap
(
  URL Text (255) UNIQUE,
  NAME Text (255) NOT NULL,
  PARENTNODEID Int32,
    CONSTRAINT NODEID PRIMARY KEY (URL, NAME)
)

Populate the table with the following kinds of data, listing files that you have in your Web site or files that you can create. The following table shows an example file listing.

NODEID URL NAME PARENTNODEID

1

Default.aspx

Default

null (empty cell)

2

Catalog.aspx

Catalog

1

3

Aboutus.aspx

Contact Us

1

NoteNote

Because data sources contain differing SQL syntax, some commands will work with one data source and not with another. As a result, it is recommended that you create a site-map provider that is specific to your data source, even if you are using the .NET Framework Data Provider for ODBC or the .NET Framework Data Provider for OLE DB to access your data source (for example, SybaseSiteMapProvider, OracleSiteMapProvider, and so on).

The AccessSiteMapProvider class derives from the StaticSiteMapProvider class, and retrieves its information from an Access database using basic SQL queries as well as OleDbCommand and OleDbDataReader objects.

Finally, AccessSiteMapProvider is configured to be the default provider in the Web.config file, as shown in the following code example.

<configuration>
  <system.web>
    <siteMap defaultProvider="AccessSiteMapProvider">
      <providers>
        <add 
          name="AccessSiteMapProvider"
          type="<type name>"
          accessSiteMapConnectionString="PROVIDER=MICROSOFT.JET.OLEDB.4.0;DATA SOURCE=<path>\sitemap.mdb "/>
      </providers> 
    </siteMap>
  </system.web>
</configuration>

To customize this example, replace <type name> with the fully qualified name of the class that implements your site-map data provider. For example, in the C# code above, you would replace <type name> with Samples.AspNet.CS.Controls.AccessSiteMapProvider. If you compile your site-map data provider code and place it in the Bin directory, the <type name> string must also include the name of your compiled file without the file name extension. For example, if you compiled the C# code above into a file called Samples.AspNet.dll, you would replace <type name> with Samples.AspNet.CS.Controls.AccessSiteMapProvider.Samples.AspNet. Lastly, replace <path> with the absolute physical path to your site-map database.

NoteNote

When you inherit from StaticSiteMapProvider, you must override the following members: BuildSiteMap and GetRootNodeCore.

Robust Programming

If you are extending the StaticSiteMapProvider class, the three most important methods are GetRootNodeCore, Initialize, and BuildSiteMap. The Clear and FindSiteMapNode methods have default implementations that are sufficient for most custom provider implementations.

See Also

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