Recently used files—Command, MultiItem, and ComboBox
RecentFilesCombo.cs
// Copyright 2010 ESRI
// 
// All rights reserved under the copyright laws of the United States
// and applicable international laws, treaties, and conventions.
// 
// You may freely redistribute and use this sample code, with or
// without modification, provided you include the original copyright
// notice and use restrictions.
// 
// See the use restrictions.
// 

using System;
using System.IO;
using System.Drawing;
using System.Runtime.InteropServices;
using ESRI.ArcGIS.ADF.BaseClasses;
using ESRI.ArcGIS.ADF.CATIDs;
using ESRI.ArcGIS.Framework;
using ESRI.ArcGIS.SystemUI;

namespace RecentFilesCommandsCS
{
  /// <summary>
  /// Command that works in ArcMap/Map/PageLayout, ArcScene/SceneControl
  /// or ArcGlobe/GlobeControl
  /// </summary>
  [Guid("39b803a3-4bbb-4099-b4d9-89273af3685d")]
  [ClassInterface(ClassInterfaceType.None)]
  [ProgId("RecentFilesCommandsCS.RecentFilesCombo")]
  public sealed class RecentFilesCombo : BaseCommand, IComboBox
  {
    #region COM Registration Function(s)
    [ComRegisterFunction()]
    [ComVisible(false)]
    static void RegisterFunction(Type registerType)
    {
      // Required for ArcGIS Component Category Registrar support
      ArcGISCategoryRegistration(registerType);
    }

    [ComUnregisterFunction()]
    [ComVisible(false)]
    static void UnregisterFunction(Type registerType)
    {
      // Required for ArcGIS Component Category Registrar support
      ArcGISCategoryUnregistration(registerType);
    }

    #region ArcGIS Component Category Registrar generated code
    /// <summary>
    /// Required method for ArcGIS Component Category registration -
    /// Do not modify the contents of this method with the code editor.
    /// </summary>
    private static void ArcGISCategoryRegistration(Type registerType)
    {
      string regKey = string.Format("HKEY_CLASSES_ROOT\\CLSID\\{{{0}}}", registerType.GUID);
      GMxCommands.Register(regKey);
      MxCommands.Register(regKey);
      SxCommands.Register(regKey);
      ControlsCommands.Register(regKey);
    }
    /// <summary>
    /// Required method for ArcGIS Component Category unregistration -
    /// Do not modify the contents of this method with the code editor.
    /// </summary>
    private static void ArcGISCategoryUnregistration(Type registerType)
    {
      string regKey = string.Format("HKEY_CLASSES_ROOT\\CLSID\\{{{0}}}", registerType.GUID);
      GMxCommands.Unregister(regKey);
      MxCommands.Unregister(regKey);
      SxCommands.Unregister(regKey);
      ControlsCommands.Unregister(regKey);
    }

    #endregion
    #endregion

    private IApplication m_application;
    private System.Collections.Generic.Dictionary<int, string> m_itemMap;
    private string m_strWidth = @"c:\documents\map documents";

    public RecentFilesCombo()
    {
      m_itemMap = new System.Collections.Generic.Dictionary<int, string>();

      base.m_category = ".NET Samples"; 
      base.m_caption = "Recent Documents: ";  
      base.m_message = "Recent Documents"; 
      base.m_toolTip = "Recent Documents";
      base.m_name = "RecentDocsCombo";
    }

    #region Overriden Class Methods

    /// <summary>
    /// Occurs when this command is created
    /// </summary>
    /// <param name="hook">Instance of the application</param>
    public override void OnCreate(object hook)
    {
      IComboBoxHook comboHook = hook as IComboBoxHook;
      if (comboHook == null)
      {
        m_enabled = false;
        return;
      }

      m_application = comboHook.Hook as IApplication;

      int cookie = 0;

      foreach (string fileName in RecentFilesRegistryHelper.GetRecentFiles(m_application))
      {
        if (File.Exists(fileName))
        {
          //Add item to list
          cookie = comboHook.Add(fileName);
          m_itemMap.Add(cookie, fileName);
        }
      }   
    }

    /// <summary>
    /// Occurs when this command is clicked
    /// </summary>
    public override void OnClick()
    {
   
    }

    #endregion

    #region IComboBox Members

    public int DropDownHeight
    {
      get { return 50; }
    }

    public string DropDownWidth
    {
      get { return m_strWidth; }
    }

    public bool Editable
    {
      get { return false; }
    }

    public string HintText
    {
      get { return "Select document"; }
    }

    public void OnEditChange(string editString)
    {
    }

    public void OnEnter()
    {
    }

    public void OnFocus(bool set)
    {
    }

    public void OnSelChange(int cookie)
    {
      string selectedPath = m_itemMap[cookie];
      m_application.OpenDocument(selectedPath);
    }

    public bool ShowCaption
    {
      get { return false; }
    }

    public string Width
    {
      get { return m_strWidth; }
    }

    #endregion

  }
}