4

我正在使用 FileSystemWatcher 来监视 app.config 文件中的任何更改。而且，写入配置文件。

这是我的代码：

MyApplication是主项目，DataCache是​​MyApplication中引用的类库。

using System;
using System.Threading;
using System.IO;
namespace MyApplication
{  

  public class Program
  {
    public static string rootFolderPath = Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);
    public static string configFilePath = Path.Combine(rootFolderPath, "MyApplication.exe.config");static void Main(string[] args)
    {
        //First Time initializing the config file.
        ConfigFileMonitor.SetConfigFileAtRuntime(configFilePath);

        //Initializing the config file monitor on a separate thread.
        Thread monitorThread = new Thread(ConfigFileMonitor.BeginConfigFilesMonitor);
        monitorThread.Start();

        WriteToConfigFile();

    }

    static void WriteToConfigFile()
    {
        Console.WriteLine(String.Format("Hello {0} {1}", DataCache.Section1Data.FirstNameString, DataCache.Section1Data.LastNameString));

        string _firstName, _lastName = string.Empty;
        do
        {
            Console.WriteLine("");
            Console.Write("First Name : ");
            _firstName = Console.ReadLine();

            Console.Write("Last Name : ");
            _lastName = Console.ReadLine();

            if(_firstName.Length>0)
                DataCache.Section1Data.FirstNameString = _firstName;

            if(_lastName.Length>0)
                DataCache.Section1Data.LastNameString = _lastName;

            Console.WriteLine(String.Format("Hello {0} {1}", DataCache.Section1Data.FirstNameString, DataCache.Section1Data.LastNameString));
        }
        while (true);
    }
  }
}


using System;
using System.IO;

namespace MyApplication
{
    /// <summary>
    /// Monitors for any change in the app.config file
    /// </summary>
    public class ConfigFileMonitor
    {
         private static FileSystemWatcher _watcher;
         private static string _configFilePath = String.Empty;
         private static string _configFileName = String.Empty;

        /// <summary>
    /// Texts the files surveillance.
    /// </summary>
    public static void BeginConfigFilesMonitor()
    {
        try
        {
            string fileToMonitor = Program.configFilePath;
            if (fileToMonitor.Length == 0)
                Console.WriteLine("Incorrect config file specified to watch");
            else
            {
                _configFileName = Path.GetFileName(fileToMonitor);
                _configFilePath = fileToMonitor.Substring(0, fileToMonitor.IndexOf(_configFileName));
            }
            // Use FileWatcher to check and update only modified text files.
            WatchConfigFiles(_configFilePath, _configFileName);
        }
        catch (Exception e1)
        {
            Console.WriteLine(e1.Message);
        }
    }

    /// <summary>
    /// Watches the files.
    /// </summary>
    /// <param name="targetDir">The target dir.</param>
    /// <param name="filteredBy">The filtered by.</param>
    static void WatchConfigFiles(string targetDir, string filteredBy)
    {
        try
        {
            _watcher = new FileSystemWatcher();
            _watcher.Path = targetDir;
            _watcher.Filter = filteredBy;
            _watcher.NotifyFilter = NotifyFilters.LastAccess | NotifyFilters.LastWrite;
            _watcher.EnableRaisingEvents = true;

            _watcher.Changed += new FileSystemEventHandler(FileChanged);
            _watcher.WaitForChanged(WatcherChangeTypes.Changed);
        }
        catch (Exception e1)
        {
            Console.WriteLine(e1.Message);
        }
    }


    /// <summary>
    /// Handles the Changed event of the File control.
    /// </summary>
    /// <param name="sender">The source of the event.</param>
    /// <param name="e">The <see cref="System.IO.FileSystemEventArgs"/> instance containing the event data.</param>
    protected static void FileChanged(object sender, FileSystemEventArgs e)
    {
        try
        {
            _watcher.EnableRaisingEvents = false;

            string filechange = e.FullPath;

            Console.WriteLine("Configuration File: " + filechange + "changed");

            //Since the file is changed - We have reload the configuration settings again.
            SetConfigFileAtRuntime(Path.Combine(Program.rootFolderPath, "MyApplication.exe.config"));

            Console.WriteLine(String.Format("New Name : {0} {1}", DataCache.Section1Data.FirstNameString, DataCache.Section1Data.LastNameString));

        _watcher.EnableRaisingEvents = true;
        }
        catch (Exception e1)
        {
            Console.WriteLine(e1.Message);
        }
    }

    /// <summary>
    /// Sets the config file at runtime.
    /// </summary>
    /// <param name="configFilePath"></param>
    public static void SetConfigFileAtRuntime(string configFilePath)
    {
        string runtimeconfigfile;
        try
        {
            if (configFilePath.Length == 0)
                Console.WriteLine("Please specify a config file to read from ");
            else
            {
                runtimeconfigfile = configFilePath;
                _configFileName = Path.GetFileName(configFilePath);
                _configFilePath = configFilePath.Substring(0, configFilePath.IndexOf(_configFileName));
            }

            // Specify config settings at runtime.
            //System.Configuration.Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
            DataCache.DataConfigSection.config = System.Configuration.ConfigurationManager.OpenExeConfiguration(configFilePath);
            //Similarly you can apply for other sections like SMTP/System.Net/System.Web etc..
            //But you have to set the File Path for each of these
            //config.AppSettings.File = runtimeconfigfile;

            //This doesn't actually going to overwrite you Exe App.Config file.
            //Just refreshing the content in the memory.
            DataCache.DataConfigSection.config.Save(System.Configuration.ConfigurationSaveMode.Modified);

            //Refreshing Config Section
            //ConfigurationManager.RefreshSection("appSettings");
            System.Configuration.ConfigurationManager.RefreshSection("MySectionGroup/Section1");                

            DataCache.Section1Data.configSection1 = null;
        }
        catch (Exception e1)
        {
            Console.WriteLine(e1.Message);
        }
    }
 }
}

<?xml version="1.0"?>
<configuration>
  <configSections>
    <sectionGroup name="MySectionGroup">
      <section name="Section1"  type="DataCache.DataConfigSection, DataCache"     allowLocation="false" allowDefinition="Everywhere"/>
      <section name="Section2"  type="DataCache.DataConfigSection, DataCache"     allowLocation="false" allowDefinition="Everywhere"/>
    </sectionGroup>
  </configSections>
  <MySectionGroup>
    <Section1>
      <name
        firstName ="Pierce"
        lastName ="Brosnan"
        />
    </Section1>
  </MySectionGroup>

<startup><supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>
</startup>

</configuration>

以下是 DataCache 类：

using System;
namespace DataCache
{
    public sealed class DataConfigSection : System.Configuration.ConfigurationSection
    {
        public static System.Configuration.Configuration config = System.Configuration.ConfigurationManager.OpenExeConfiguration(
        System.IO.Path.Combine(System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetAssembly(typeof(DataConfigSection)).Location), "MyApplication.exe"));

    // Create a "name" element.
    [System.Configuration.ConfigurationProperty("name")]
    public NameElement Name
    {
        get
        {
            return (NameElement)this["name"];
        }
        set
        {
            this["name"] = value;
        }
    }

    // Define the "name" element
    // with firstName, secondName attributes.
    public class NameElement : System.Configuration.ConfigurationElement
    {
        [System.Configuration.ConfigurationProperty("firstName", DefaultValue = "abcd", IsRequired = true)]
        public String FirstName
        {
            get
            {
                return (String)this["firstName"];
            }
            set
            {
                this["firstName"] = value;
            }
        }

        [System.Configuration.ConfigurationProperty("lastName", DefaultValue = "xyz", IsRequired = true)]
        public String LastName
        {
            get
            {
                return (String)this["lastName"];
            }
            set
            {
                this["lastName"] = value;
            }
        }
    }
  }
}


namespace DataCache
{
    public class Section1Data
    {
        public static volatile DataConfigSection configSection1;
        private static object syncRoot = new System.Object();

    public const string Section1ConfigSectionName = "MySectionGroup/Section1";

    private Section1Data() { }

    public static DataConfigSection ConfigSection1
    {
        get
        {
            lock (syncRoot)
            {
                if (configSection1 == null)
                {
                    DataConfigSection.config = System.Configuration.ConfigurationManager.OpenExeConfiguration(System.IO.Path.Combine(System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetAssembly(typeof(DataConfigSection)).Location), "MyApplication.exe"));
                    configSection1 = (DataConfigSection)DataConfigSection.config.GetSection(Section1ConfigSectionName);                   
                }
            }
            return configSection1;
        }
    }
    public static string FirstNameString
    {
        get
        {
            return ConfigSection1.Name.FirstName.ToString();
        }
        set
        {
            ConfigSection1.Name.FirstName = value;
            DataConfigSection.config.Save();
        }
    }
    public static string LastNameString
    {
        get
        {
            return ConfigSection1.Name.LastName.ToString();
        }
        set
        {
            ConfigSection1.Name.LastName = value;
            DataConfigSection.config.Save();
        }
    }
  }
}

问题是，如果从控制台输入对名称进行了任何更改，则 FileChanged 会被调用一次，并且后续更改不会触发它。此外，如果手动对配置文件进行更改，它可以正常工作，直到从控制台进行更改为止，事件会一直触发。

我不确定为什么这行为很奇怪。有人能帮我一下吗。

谢谢，莫妮卡

4

2 回答 2

2

简短版本是：

this.Watcher = new FileSystemWatcher();
this.Watcher.Path = this.Dir;
this.Watcher.Filter = this.File;
this.Watcher.NotifyFilter = NotifyFilters.LastWrite | NotifyFilters.FileName | NotifyFilters.DirectoryName;
this.Watcher.EnableRaisingEvents = true;
this.Watcher.Changed += this.OnFileChange;

但是，这里有一个更复杂（和丑陋）的示例，它是从需要一些额外处理（除了读取文件之外）的实时源中取出的。

public partial class FileModule
{
    private ConcurrentDictionary<string, InputFileInfo> inputFileList = new ConcurrentDictionary<string, InputFileInfo>();

    public FileModule()
    {
        this.InitializeInputFileWatchers();
    }

    [PermissionSet(SecurityAction.Demand, Name = "FullTrust")]
    public void EnableOrDisableRaisingEventsForFileWatchers(bool enable)
    {
        foreach (var el in this.inputFileList)
        {
            el.Value.Watcher.EnableRaisingEvents = enable;
        }
    }

    [PermissionSet(SecurityAction.Demand, Name = "FullTrust")]
    private void InitializeInputFileWatchers()
    {
        for (int i = 0; i < this.InputFiles.Count; i++)
        {
            if (File.Exists(this.InputFiles[i]))
            {
                InputFileInfo info = new InputFileInfo();
                info.Fullpath = ((FileModuleSettings)this.Settings).InputFiles[i];
                info.Watcher.Changed += this.OnFileChange;

                this.inputFileList.AddOrUpdate(info.Fullpath, info, (e, v) => { return info; });
            }
        }
    }

    [PermissionSet(SecurityAction.Demand, Name = "FullTrust")]
    private void OnFileChange(object source, FileSystemEventArgs e)
    {
        InputFileInfo info;
        if (this.inputFileList.TryGetValue(e.FullPath, out info))
        {
            DateTime lastWriteTime = System.IO.File.GetLastWriteTime(e.FullPath);
            if (info.LastHandledChange != lastWriteTime)
            {
                TimeSpan span = lastWriteTime.Subtract(info.LastHandledChange);
                if (span.Days == 0 && span.Hours == 0 && span.Minutes == 0 && span.Seconds == 0 && span.TotalMilliseconds < this.MinimumFileChangePeriod)
                {
                    // Event ignored due to required minimum file change period;
                }
                else
                {
                    info.LastHandledChange = lastWriteTime;
                    this.inputFileList.AddOrUpdate(e.FullPath, info, (a, v) => { return info; });

                    lock (this.readLockerObject)
                    {
                        this.ReadFile(e.FullPath);
                    }
                }
            }
        }
    }

    private bool ReadFile(string filepath, int count, bool directReading)
    {
        StreamReader sr = this.OpenStreamReader(file);

        if (sr != null)
        {
            string line;
            string[] split;
            int signalId;
            double value;

            while ((line = sr.ReadLine()) != null)
            {
                // do sth. with line
            }
        }
    }
}

internal class InputFileInfo : IDisposable
{
    public string Dir { get; private set; }

    public string File { get; private set; }

    public FileSystemWatcher Watcher { get; private set; }

    public DateTime LastHandledChange { get; set; }

    private string fullpath;

    public string Fullpath
    {
        get
        {
            return this.fullpath;
        }

        set
        {
            this.fullpath = BaseHelper.GetFullFilePath(value);
            this.Dir = Directory.GetParent(this.fullpath).ToString();
            this.File = this.fullpath.Replace(this.Dir + "\\", string.Empty);
            this.Watcher = new FileSystemWatcher();
            this.Watcher.Path = this.Dir;
            this.Watcher.Filter = this.File;
            this.Watcher.NotifyFilter = NotifyFilters.LastWrite | NotifyFilters.FileName | NotifyFilters.DirectoryName;
            this.Watcher.EnableRaisingEvents = true;
        }
    }

    public void Dispose()
    {
        if (this.Watcher != null)
        {
            this.Watcher.Dispose();
            this.Watcher = null;
        }
    }
}
于 2013-01-02T14:47:48.773 回答
0

你有非常复杂的代码。我的 watcher 代码大约有 10 行。

无需将观察者的初始化卸载到另一个线程。在主线程上初始化它。观察者在后台线程中监视文件并在发生更改时触发事件，因此无需调用 WaitForChanged() 方法。

我检查了我的工作代码并将其与您的代码进行了比较，唯一的两个区别是： 1. 我的过滤器是： NotifyFilters.LastWrite | NotifyFilters.文件名 | NotifyFilters.DirectoryName 2. 我不调用 WaitForChanged() 方法 3. 我已 [PermissionSet(SecurityAction.Demand, Name = "FullTrust")]应用到所有与观察者交互的方法。

此外，请确保您正在监视的文件不在系统目录之一中...观察程序无法很好地处理这些文件。我在墙上撞了半天，因为我试图在 C: 上观看文件。

于 2012-12-28T20:41:49.813 回答