Application Auto Update Revisited

1. Create a project - click File -> New -> Project -> Class Library
1.1. Name it whatever you want (as long as its name is AutoUpdate )
1.2. Rename Class1.cs to AutoUpdate.cs (accepting to rename all references)
1.2. Double click AutoUpdate.cs and paste (replace whatever is in there) the following listing

Project: AutoUpdate<br/>
File: AutoUpdate.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Diagnostics;
using System.Windows.Forms;

/// <summary>
/// Class to update .exe and .dll through HTTP connection
/// </summary>
/// <author>Eduardo Oliveira</author>
/// <Modified_by>Danny (dbembibre@virtualdesk.es)</Modified_by>
/// <history Danny>
/// Changed: C# translated and retouched
/// Changed: Added method IsUpdatable() to verify if a new update exists
/// Changed: Now you can update any file without need of exe file
/// Changed: If something went wrong, you have a collection to rollback all files to the original state
///</history Danny>
/// <Modified>Tiago Freitas Leal, Feb. 2008 - v.2.1.1</Modified>
/// <history TFL>
/// Changed: General refactoring of names
/// Changed: Refactoring of properties to constants (preparing for resources)
/// Changed: Remote URI doesn't depend on assembly name
/// Changed: Ignore heading "." and "\" on file paths
/// Changed: Ignore second instance of same file path
/// Changed: Add "=ExactVersion" option
/// Changed: ".ToDelete" filenames are prefixed with the old filename (avoid duplicate names)
/// Changed: "return" happens always after "Dispose" operations
/// Changed: Merge "IsUpdatable" into "UpdateFiles"
/// Changed: Move delete operations to new public CleanUp() method
/// Changed: Files to be deleted are made NOT ReadOnly before deletion
/// Changed: Delete operates also on sub-directories
///</history TFL>
public class AutoUpdate
{
    // <File Path>;<MinimumVersion>   [' comments    ]
    // <File Path>;=<ExactVersion>    [' comments    ]
    // <File Path>;                   [' comments    ]
    // <File Path>;?                  [' comments    ]
    // <File Path>;delete             [' comments    ]
    // ...
    // Blank lines and comments are ignored
    // First parameter - file path (eg. Dir\file.dll)
    // Second parameter:
    // If the version is specified, the file is updated if:
    //   - it doesn't exist or
    //   - the actual version number is smaller than the update version number
    // If the version is specified precedeed by a "=", the file is updated if:
    //   - it doesn't exist or
    //   - the actual version doesn't match the update version
    // If it's an interrogation mark "?" the file is updated only if it doesn't exist
    // If the second parameter is not specified, the file is updated only if it doesn't exist (just like "?")
    // If it's "delete" the system tries to delete the file
    // "'" (chr(39)) start a line (or part line) comment (like VB)

    // Method return values
    //   - True - the update was done with no errors
    //   - False - the update didn't complete successfully: either there is no update to be done
    //             or there was an error during the update

    // NB - "Version" refers to the AssemblyFileVersion as configured in file AssemblyInfo.cs

    private const string ToDeleteExtension = ".ToDelete";
    private const string UpdateFileName = "Update.txt";
    private const string ErrorMessageCheck = "There was a problem checking the update config file.";
    private const string ErrorMessageUpdate = "There was a problem runing the Auto Update.";
    private const string ErrorMessageDelete = "There was a problem deleting files.";

    #region "CleanUp"

    public static bool CleanUp()
    {
        try
        {
            string file;

            DirectoryInfo dir = new DirectoryInfo(Application.StartupPath);
            FileInfo[] infos = dir.GetFiles("*" + ToDeleteExtension, SearchOption.AllDirectories);
            foreach (FileInfo info in infos)
            {
                file = info.FullName;
                File.SetAttributes(file, FileAttributes.Normal);
                File.Delete(file);
            }
            return true;
        }
        catch (Exception ex)
        {
            MessageBox.Show(ErrorMessageDelete + "\r" + ex.Message);
            return false;
        }
    }

    #endregion

    #region "UpdateFiles"

    public static bool UpdateFiles(string remotePath, bool DoUpdate)
    {
        if (remotePath == string.Empty)
            return false;

        if (DoUpdate)
        {
            // Delete files before updating them
            CleanUp();
        }

        // execute the following line even for check runs
        System.Collections.Generic.List<AutoUpdateRollback> rollBackList =
            new System.Collections.Generic.List<AutoUpdateRollback>();

        string remoteUri = remotePath;
        WebClient myWebClient = new WebClient();

        bool retValue = false;
        try
        {
            // Get the remote file
            string contents = myWebClient.DownloadString(remoteUri + UpdateFileName);
            // Strip the "LF" from CR+LF and break it down by line
            contents = contents.Replace("\n", "");
            string[] fileList = contents.Split(Convert.ToChar("\r"));

            // Parse the file list to strip comments
            contents = string.Empty;
            foreach (string file in fileList)
            {
                string fileAux;
                if ((file.IndexOf("\'") + 1 != 0))
                    fileAux = file.Substring(0, ((file.IndexOf("\'") + 1) - 1));
                else
                    fileAux = file;
                if (fileAux.Trim() != string.Empty)
                {
                    if (!string.IsNullOrEmpty(contents))
                        contents = contents + (char) (Keys.Return);
                    contents = contents + fileAux.Trim();
                }
            }

            // Parse the file list again
            fileList = contents.Split((char) (Keys.Return));
            string[] info;
            string infoFilePath;
            String infoParam;
            List<string> fileNameList = new List<string>();
            Version Version1, Version2;
            FileVersionInfo fv;
            bool IsToDelete;
            bool IsToUpgrade;
            foreach (string file in fileList)
            {
                info = file.Split(Convert.ToChar(";"));
                infoFilePath = info[0].Trim();
                infoParam = info[1].Trim();
                while (infoFilePath[0] == '.' || infoFilePath[0] == '\\')
                {
                    infoFilePath = infoFilePath.Substring(1, infoFilePath.Length-1);
                }

                // ignore path names already on list (duplicates)
                if (fileNameList.Contains(infoFilePath.ToLowerInvariant()))
                {
                    continue;
                }

                // add path name to list
                fileNameList.Add(infoFilePath.ToLowerInvariant());
                IsToDelete = false;
                IsToUpgrade = false;
                string fileName = Application.StartupPath + @"\" + infoFilePath;
                string tempFileName = Application.StartupPath + @"\" + infoFilePath + DateTime.Now.TimeOfDay.TotalMilliseconds;
                bool FileExists = File.Exists(fileName);
                if ((infoParam == "delete"))
                {
                    IsToDelete = FileExists; // The second parameter is "delete"
                    if (DoUpdate)
                        if (IsToDelete)
                            rollBackList.Add(new AutoUpdateRollback(fileName, tempFileName + ToDeleteExtension, "Delete"));
                }
                else if ((infoParam == "?"))
                {
                    // The second parameter is "?" (check if the file exists and it TRUE, do not update
                    IsToUpgrade = !FileExists;
                }
                else if (infoParam != string.Empty && (infoParam[0] == '=' && FileExists))
                {
                    // The second parameter starts by "=" 
                    // Check the version of local and remote files
                    fv = FileVersionInfo.GetVersionInfo(fileName);
                    Version1 = new Version(infoParam.Substring(1, infoParam.Length - 1));
                    Version2 = new Version(fv.FileVersion);
                    IsToUpgrade = Version1 != Version2;
                    IsToDelete = IsToUpgrade;
                    if (DoUpdate)
                        if (IsToUpgrade)
                            rollBackList.Add(
                                new AutoUpdateRollback(fileName, tempFileName + ToDeleteExtension, "Upgrade"));
                }
                else if (FileExists)
                {
                    // Check the version of local and remote files
                    fv = FileVersionInfo.GetVersionInfo(fileName);
                    // If 2nd parameter is empty, do nothing as file already exists
                    if (infoParam != string.Empty)
                    {
                        Version1 = new Version(infoParam);
                        Version2 = new Version(fv.FileVersion);
                        IsToUpgrade = Version1 > Version2;
                        IsToDelete = IsToUpgrade;
                        if (DoUpdate)
                            if (IsToUpgrade)
                                rollBackList.Add(
                                    new AutoUpdateRollback(fileName, tempFileName + ToDeleteExtension, "Upgrade"));
                    }
                }
                else
                {
                    IsToUpgrade = true;
                }

                if (DoUpdate)
                {
                    if (IsToUpgrade)
                        myWebClient.DownloadFile(remoteUri + infoFilePath, tempFileName);
                    // Rename the file for future deletion
                    if (IsToDelete)
                        File.Move(fileName, tempFileName + ToDeleteExtension);
                    // Rename the temporary file name to the real file name
                    if (IsToUpgrade)
                        File.Move(tempFileName, fileName);
                }

                if (IsToUpgrade || IsToDelete)
                    retValue = true;
            }

            // This reruns the updated application
            //Process.Start(Application.ExecutablePath);
            // Don't use it here or you will end in an endless loop.
        }
        catch (Exception ex)
        {
            MessageBox.Show("There was an error. Trying to roll back");
            if (DoUpdate)
            {
                foreach (AutoUpdateRollback rollBack in rollBackList)
                {
                    if (rollBack.Operation == "Delete" || rollBack.Operation == "Upgrade")
                    {
                        if (File.Exists(rollBack.Renamed))
                            File.Move(rollBack.Renamed, rollBack.Original);
                    }
                }
                MessageBox.Show(ErrorMessageUpdate + "\r" + ex.Message + "\r" + "Remote URI: " + remoteUri);
            }
            else
                MessageBox.Show(ErrorMessageCheck + "\r" + ex.Message + "\r" + "Remote URI: " + remoteUri);

            retValue = false;
        }
        finally
        {
            myWebClient.Dispose();
            // execute the following line even for check runs
            rollBackList.Clear();
        }

        return retValue;
    }

    #endregion
}

public class AutoUpdateRollback
{
    #region Properties

    private string _renamed, _original, _operation;

    public string Operation
    {
        get { return _operation; }
        set { _operation = value; }
    }

    public string Original
    {
        get { return _original; }
        set { _original = value; }
    }

    public string Renamed
    {
        get { return _renamed; }
        set { _renamed = value; }
    }

    #endregion

    #region Constructor

    public AutoUpdateRollback(string Original, string Renamed, string Operation)
    {
        _original = Original;
        _renamed = Renamed;
        _operation = Operation;
    }

    #endregion
}

Project: Updated<br/>
File: ShowVersionForm.cs

using System;
using System.Diagnostics;
using System.Reflection;
using System.Windows.Forms;

namespace Updated
{
    public partial class ShowVersionForm : Form
    {
        public ShowVersionForm()
        {
            InitializeComponent();
            label2.Text = FileVersionInfo.GetVersionInfo(Assembly.GetExecutingAssembly().Location).FileVersion;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Close();
        }
    }
}

Project: AutoUpdateTest<br/>
File: Startup.cs

using System;
using System.Diagnostics;
using System.Windows.Forms;

namespace AutoUpdateTest
{
    public partial class Startup : Form
    {
        public Startup()
        {
            InitializeComponent();
        }

        private void Startup_Load(object sender, EventArgs e)
        {
            Show();

            //Change to reflect your RemotePath
            string RemotePath = "http://localhost/AutoUpdateTest/";
            label1.Text = RemotePath;
            Form helper = new Updated.ShowVersionForm();
            helper.Show();
            MessageBox.Show("Checking if update is needed...");
            if (AutoUpdate.UpdateFiles(RemotePath, false))
            {
                MessageBox.Show("Update is needed.");
                if (AutoUpdate.UpdateFiles(RemotePath, true))
                {
                    MessageBox.Show("Auto Update succedeed!");
                    Dispose();
                    Process.Start(Application.ExecutablePath); 
                    Application.Exit();
                }
            }
            else
            {
                MessageBox.Show("No update is available.");
                AutoUpdate.CleanUp();
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Close();
        }
    }
}

\Updated2.exe ; 'Get Updated2.exe if it doesn't exist (ignore "\")
 .\Updated3.exe ; ? 'Get Updated3.exe if it doesn't exist (ignore ".\")
 .\Updated3.exe ; delete 'This line is ignored as it's the second instance of the same file path
 ..\Updated4.exe ; =1.0.0.3 'If actual Updated4.exe isn't this version, get it (ignore "..\")
 Updated5.exe ; delete 'Delete Updated5.exe
 Updated.exe ; 1.0.0.3 'If actual Updated.exe version is smaller than 1.0.0.3, get it 
 'Update2.exe ; delete 'ignore this line
'the lines below just test the same features on sub-directories
 TST\TSTUpdated.dll ; 1.0.0.1 
 TST\SubSub\SUBUpdated.dll ; 1.0.0.1 
 \TST\SubSub\Slash.dll ; 1.0.0.1 
 .\TST\SubSub\DotSlash.dll ; 1.0.0.1 
 .\TST\SubSub\Trash.dll ; delete