WIndows CE Notes.Links

• Cannot call BeginInvoke on a delegate in WIndows CE version of .NET
• Open Net Compact framework Library

Initializing A ComboBox In CE.NET With The Values of An Enum

  SomeEnum status;
  int offset = 0;
  bool defined = false;
  do
  {
      status = (SomeEnum)offset++;
      defined = Enum.IsDefined(typeof(SomeEnum), status.ToString());
      if (defined)
      {
          comboBox.Items.Add(status);
      }

  } while (IsDefined);
  comboBox.SelectedIndex = 0;

Using A ListView

To get a nice excel type view of the list set the properties 'View=Details' and 'GridLines=True' or put the following code in the designer

//this.listView.Anchor =  //Dont forget to set the anchors appropriately
this.listView.AllowColumnReorder = true;
this.listView.View = System.Windows.Forms.View.Details; 
this.listView.GridLines = true;

// Select highlights a full row
this.listView.FullRowSelect = true;

// Select a single row only
this.listView.MultiSelect = false;

// Keep selected rows highlited even when the control does not have the focus 
this.listView.HideDelection = false; 

Adding items to the ListView

private const int NAME_COLUMN = 0;
private const int ID_COLUMN = 1;

void PopulateListView()
{
    // DONT call "listView.Clear()" or you'll lose all your
    // column data and then wonder why you table is empty!
    listView.Items.Clear(); 
    // Add the item to the ListView
    string[] fields = new string[] 
    { 
        "column1string", 
        "column2string", 
        ... 
    };
OR
    fields[NAME_COLUMN] = xxx.Name;
    fields[ID_COLUMN] = xxx.Id.ToString();
    ...

    ListViewItem lvItem = new ListViewItem(fields);
    // Insert at the top of the listview control
    listView.Items.Insert(0, lvItem);
    // Append to the end of the ListView control
    listView.Items.Add(lvItem);

    // with custom listviewitems
    MyListViewItem li = new MyListViewItem(...)
    listView.Items.Add(li);
}

To update a column:

private void UpdateIdColumn(int id)
{
    listView.Items[m_SelectedIndex].SubItems[ID_COLUMN].Text = id.ToString();
}

Optionally define a custom list view item which holds a reference to one of your types XXX

internal class MyListViewItem : ListViewItem
{
    internal MyListViewItem(XXX xxx)
        : base(new string[] { 
                    xxx.Name, 
                    xxx.Description, 
                })
    {
        XXX = xxx;
    }

    internal XXX XXX { get; set; }
}

private void listView_SelectedIndexChanged(object sender, EventArgs e)
{
    if (listView.SelectedItems.Count == 0)
    {
 // Are there any controls need enabling/
 // disabling when the nothing is selected
        button.Enabled = false;
        return;
    }
 
    // Are there any controls need enabling/
    // disabling when the nothing is selected
    otherCtrl.Enabled = true;
 
    foreach (ListViewItem lvi in lvParts.SelectedItems)
    {
        ((XXX)lvi.Tag).DoSomething();
 // or
        MyCustomListItem li = lvi as MyCustomListItem;
        if (li != null)
        {
            li.XXX.DoSomething(); 
        }
        break;
    }
}

Dont forget to add a method to resize the columns:

private void FitColumnsToListView()
{
    int extra = ListViewSpareColumnSpace(lvParts);
    if (extra > 0)
    {
        lvParts.Columns[0].Width += extra;
    }
}

private int ListViewSpareColumnSpace(ListView lv)
{
    if (lv.Columns.Count == 0)
        return 0;

    int width = lv.Size.Width;
    int usedWidth = 0;
    // 2 pixels for the divider lines
    foreach (ColumnHeader ch in lv.Columns)
    {
        usedWidth += ch.Width + 2;
    }
    int extra = width - usedWidth;
    return extra;
}

To disable selection of listview items, handle the ItemSelectionChanged event on the listView:

private void listView_ItemSelectionChanged(object sender, 
  ListViewItemSelectionChangedEventArgs e)
{
  if (e.IsSelected)
    e.Item.Selected = false;
}

Use Reflection To Set A Value On A Field

Setting a field on an object by reflection private static void SetFieldViaReflection( object obj, string fieldName, object value) { Type InstanceType = Instance.GetType(); FieldInfo fi = InstanceType.GetField(fieldName, BindingFlags.NonPublic | BindingFlags.Instance); if (fi != null) { fi.SetValue(obj, value); } } SetFieldByReflection(object, "m_field", somevalue as object);

Boxing with C#

Theres nothing like learning by trying. Here is some code that I wrote that explicitly demonstrates boxing. I found in MSDN a little boxing test so I copied the balls of it (hope thats not illegal or anything) to here. The original article can be found through a quick google search. It is a good article on boxing.

Thread Pattern Starter Class

Background thread class as a starter for a threading class.

class WorkerThread
{

    public WorkerThread()
    {
        StartThread();
    }

    ~WorkerThread()
    {
        Dispose(false);
    }

    #region IDisposable Members

    private bool m_disposed = false;

    public void Dispose()
    {
        Dispose(true);
        GC.SuppressFinalize(this);
    }

    protected virtual void Dispose(bool disposing)
    {
        if (!m_disposed)
        {
            if (disposing)
            {
                // Dispose managed resources
            }

            // Dispose unmanaged resources
            EndThread();
        }
        m_disposed = true;
    }

    #endregion



    #region Private Threading Related

    /// <summary>
    /// Actual threa object
    /// </summary>
    private Thread m_Thread = null;

    /// <summary>
    /// Give the thread a meaningful threadId
    /// </summary>
    private string threadId = "MyThreadName";

    /// <summary>
    /// Time to wait for the thread to finish 
    /// when merging the thread  
    /// back to the  main thread
    /// </summary>
    private uint waitForEndThread = 5000; // 5 seconds

    /// <summary>
    /// How long to pause for at the end of each iteration 
    /// </summary>
    private int m_ThreadSleepPeriod = 200;

    /// <summary>
    /// We use the m_PauseEvent to control the sleep period 
    /// of the thread. The m_PauseEvent
    /// sleeps for the given period  but we can force it to 
    /// wake up early by calling  
    /// Set on it.
    /// </summary>
    private AutoResetEvent m_PauseEvent = new AutoResetEvent(false);

    /// <summary>
    /// This does not need special protected access.
    /// It is set to false before the thread is  
    /// started  and  can  only get set to  true when 
    /// the  thread thread has begun.
    /// </summary>
    private bool m_Stop = false;

    /// <summary>
    /// Start the thread running
    /// </summary>
    private void StartThread()
    {
        if (m_Thread != null)
        {
            EndThread();
        }

        if (m_Thread == null)
        {
            if (m_PauseEvent == null)
            {
                m_PauseEvent = new AutoResetEvent(false);
            }
            m_Stop = false;
            m_Thread = new Thread(new ThreadStart(
this.ThreadRoutine));
            m_Thread.IsBackground = true;
            m_Thread.Start();
            m_Thread.Name = threadId;
            Thread.Sleep(0);
        }
    }

    ///  <summary>
    ///  EndThread to the thread to terminate it
    ///  </summary>
    private void EndThread()
    {
        m_Stop = true;
        if (m_Thread != null)
        {
            if (m_PauseEvent != null)
            {
                m_PauseEvent.Set();
            }

            try
            {
                if (m_Thread.IsAlive)
                {
                    System.Diagnostics.Debug.WriteLine(
"WorkerThread.EndThread(): EndThreading this thread  \'"+ 
m_Thread.Name + "\' to \'" + Thread.CurrentThread.Name + "\'");
                    // Wait X seconds for the thread to finish
                    if (!m_Thread.Join((int)waitForEndThread)) 
                    {
                        System.Diagnostics.Debug.WriteLine(
"WorkerThread.EndThread(): EndThread() failed, so ABORTing thread\'" + 
m_Thread.Name + "\'");
                        m_Thread.Abort(); // otherwise abort
                    }
                    else
                    {
                        System.Diagnostics.Debug.WriteLine(
"WorkerThread.EndThread(): EndThread() succeeded, Thread \'"+ 
m_Thread.Name + "\' is terminated");
                    }
                }
                else
                {
                    System.Diagnostics.Debug.WriteLine(
"WorkerThread.EndThread(): Thread \'" +
 m_Thread.Name + "\'  is not 'Alive' so EndThread() not invoked");
                }
            }
            catch (System.Threading.ThreadStateException ex)
            {
                // Swallow any ThreadStateExceptions
                System.Diagnostics.Debug.WriteLine(
"WorkerThread.EndThread(): ThreadStateException caught in  thread \'" + 
m_Thread.Name + "\'" + ex.ToString());
            }
            m_Thread = null;
            if (m_PauseEvent != null)
            {
                m_PauseEvent.Close();
                m_PauseEvent = null;
            }
        }
    }

    ///  <summary>
    ///  The routine executed within the new thread
    ///  </summary>
    private void ThreadRoutine()
    {
        string thrdName = m_Thread.Name;
        System.Diagnostics.Debug.WriteLine("Thread \'" + 
thrdName + "\'  thread routine is started");
        try
        {
            while (m_Stop != true)
            {
                ThreadWork();
                if ((m_Stop != true) &&
                    (m_ThreadSleepPeriod >= 0))
                {
                    m_PauseEvent.WaitOne(m_ThreadSleepPeriod,
 false);
                }
            }
        }
        catch (Exception ex)
        {
            m_Stop = true;
            //if (log  != null)
            System.Diagnostics.Debug.WriteLine(
"FATAL exception caught in thread  routine  \'" + 
thrdName.ToString() + "\' Thread will be terminated" + ex.ToString());
        }
        System.Diagnostics.Debug.WriteLine("Thread \'" + thrdName + 
"\' end of thread routine reached");
    }

    private void ThreadWork()
    {
        // Do something
    }

    #endregion

}

Windows Service Pattern

Use this template as an example for creating a service.
Note that XXX is the service implementation class, this class just integrates that service object into windows services.

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.ServiceProcess;
using System.Runtime.Remoting;

using Logging = log4net;

namespace XXX.service
{
  /// <summary>
  /// Main service class as created by the code generator.
  /// </summary>
  public class XXXService 
  {
    #region Logging

    private static readonly Logging.ILog log =   
        Logging.LogManager.GetLogger(typeof(XXXService));

    #endregion Logging

    /// <summary>
    /// 
    /// </summary>
    public static readonly string ServiceDisplayName =
        "XXXService";

    #region Private Fields

    /// <summary> 
    /// Required designer variable.
    /// </summary>
    private System.ComponentModel.Container components
        = null;

    /// <summary>
    /// Did the service start up successfully
    /// </summary>
    private bool startSuccesful = false;

    #endregion Private Fields

    #region Constructor

    /// <summary>
    /// XXXService constructor.
    /// </summary>
    public XXXService()
    {
      // This call is required by the Windows.Forms
      // Component Designer.
      InitializeComponent();
    }

    #endregion Constructor

    #region Main/Initialise

    // The main entry point for the process
    static void Main()
    {
      System.ServiceProcess.ServiceBase[] ServicesToRun;
  
      // More than one user Service may run within the
      // same process. To add another service to this 
      // process, change the following line to
      // create a second service object. For example,
      //
      //   ServicesToRun = new
      //    System.ServiceProcess.ServiceBase[] { 
      //        new XXXService(),
      //        new MySecondUserService() };
      //
      ServicesToRun = new System.ServiceProcess.ServiceBase[] 
        { new XXXService() };

      System.ServiceProcess.ServiceBase.Run(ServicesToRun);
    }

    /// <summary> 
    /// Required method for Designer support - do not modify 
    /// the contents of this method with the code editor.
    /// </summary>
    private void InitializeComponent()
    {
      components = new System.ComponentModel.Container();
      this.ServiceName = ServiceDisplayName;
    }

    #endregion  Main/Initialise

    #region IDispose Implementation

    /// <summary>
    /// Clean up any resources being used.
    /// </summary>
    protected override void Dispose( bool disposing )
    {
      if( disposing )
      {
        if (components != null) 
        {
          components.Dispose();
        }
      }
      base.Dispose( disposing );
    }

    #endregion IDispose Implementation

    #region Service Methods

    private bool IsDebugParameter(string arg)
    {
      var param = arg.ToUpperInvariant();

      return (param == "-DEBUG") || (param == "/DEBUG");
    }

    /// <summary>
    /// Set things in motion so your service can do its work.
    /// </summary>
    protected override void OnStart(string[] args)
    {
      // Allow us to be run in a debugger - for
      // development time support.
      if ((args.Length == 1) && IsDebugParameter(args[0]))
        Debugger.Launch();

      startSuccesful = false;
      string fileName = string.Empty;
      try
      { 
        log.Info("OnStart: Starting \'" + ServiceDisplayName<br> + "\'");

        System.IO.FileInfo fi = new System.IO.FileInfo(
            System.Windows.Forms.Application.ExecutablePath);
        System.Environment.CurrentDirectory = 
            fi.Directory.ToString();
        log.Info("Setting current directory to " 
            + System.Environment.CurrentDirectory);
        fileName = System.Windows.Forms.Application.ExecutablePath 
            + ".config";
        log.Info("Loading configuration from " + fileName);
        
        // If you have a remoting object that is 
        // initialised within the Config file       
        // initialise it here.
        // RemotingConfiguration.Configure(fileName);
            
        // Initialise 
        log.Info("OnStart: About to create XXX.");
        
        XXX xxx = new XXX(); // Service implementation class
        xxx.Initialise();
        
        // We assume that if the XXX is not constructed and 
        // initialised correctly it will throw an exception.
        // If we get to this point without an exception 
        // being thrown we assume 'alles ist gut'
        startSuccesful = true; 
        log.Info("OnStart: Started \'" + ServiceDisplayName 
            + "\' successfully=" + startSuccesful.ToString());
      }
      catch(Exception ex)
      {
        string errorMsg = 
          "Exception occured while starting service\'" 
            + ServiceDisplayName 
            + "\'. Expect an error message dialog");
        log.Fatal(errorMsg, ex);
        throw; // Results in error message: "XXX 
        // service on Local Computer started and 
        // then stopped. Some services stop if they 
        // have no work to do, for example, the 
        // Performance Logs and Alert service        
      }   
      if (startSuccesful)
      {
        // Tell the rest of the world we are running.
        ... 
      }
    }
 
    /// <summary>
    /// Stop this service.
    /// </summary>
    protected override void OnStop()
    {
      log.Info("OnStop: Stopping \'" + ServiceDisplayName<br> + "\'");
      
      if (xxx != null)
      {
        xxx.Dispose(); 
        ... 
      }
      
      if (startSuccesful)
      {
        // 
      }
      log.Info("OnStop: Stopped \'" + ServiceDisplayName<br> + "\'");
    }

    #endregion Service Methods

  }