C# - 用户设置损坏

Question

我们在读取标准 .Net 用户设置时发生了一个罕见的异常(这是在 VS 2008 的“项目属性”中找到的):

System.Configuration.ConfigurationErrorsException was caught
  Message="Configuration system failed to initialize"
  Source="System.Configuration"
  BareMessage="Configuration system failed to initialize"
  Line=0
  StackTrace:
       at System.Configuration.ConfigurationManager.PrepareConfigSystem()
       at System.Configuration.ConfigurationManager.GetSection(String sectionName)
       at System.Configuration.PrivilegedConfigurationManager.GetSection(String sectionName)
       at System.Diagnostics.DiagnosticsConfiguration.GetConfigSection()
       at System.Diagnostics.DiagnosticsConfiguration.Initialize()
       at System.Diagnostics.DiagnosticsConfiguration.get_IndentSize()
       at System.Diagnostics.TraceInternal.InitializeSettings()
       at System.Diagnostics.TraceInternal.get_Listeners()
  InnerException: System.Configuration.ConfigurationErrorsException
       Message="Unexpected end of file has occurred. The following elements are not closed: setting, SettingsTest.Properties.Settings, userSettings, configuration. Line 7, position 1. (C:\\Documents and Settings\\USER\\Local Settings\\Application Data\\Hitcents\\SettingsTest.vshost.exe_Url_ghwhc20utv4toanuinmj0pfsljthcugo\\1.0.0.0\\user.config line 7)"
       Source="System.Configuration"
       BareMessage="Unexpected end of file has occurred. The following elements are not closed: setting, SettingsTest.Properties.Settings, userSettings, configuration. Line 7, position 1."
       Filename="C:\\Documents and Settings\\USER\\Local Settings\\Application Data\\Hitcents\\SettingsTest.vshost.exe_Url_ghwhc20utv4toanuinmj0pfsljthcugo\\1.0.0.0\\user.config"
       Line=7
       StackTrace:
            at System.Configuration.ConfigurationSchemaErrors.ThrowIfErrors(Boolean ignoreLocal)
            at System.Configuration.BaseConfigurationRecord.ThrowIfParseErrors(ConfigurationSchemaErrors schemaErrors)
            at System.Configuration.BaseConfigurationRecord.ThrowIfInitErrors()
            at System.Configuration.ClientConfigurationSystem.OnConfigRemoved(Object sender, InternalConfigEventArgs e)
       InnerException: System.Xml.XmlException
            Message="Unexpected end of file has occurred. The following elements are not closed: setting, SettingsTest.Properties.Settings, userSettings, configuration. Line 7, position 1."
            Source="System.Xml"
            LineNumber=7
            LinePosition=1
            SourceUri=""
            StackTrace:
                 at System.Xml.XmlTextReaderImpl.Throw(Exception e)
                 at System.Xml.XmlTextReaderImpl.Throw(String res, String arg)
                 at System.Xml.XmlTextReaderImpl.Throw(Int32 pos, String res, String arg)
                 at System.Xml.XmlTextReaderImpl.ThrowUnclosedElements()
                 at System.Xml.XmlTextReaderImpl.ParseElementContent()
                 at System.Xml.XmlTextReaderImpl.Read()
                 at System.Xml.XmlTextReader.Read()
                 at System.Xml.XmlTextReaderImpl.Skip()
                 at System.Xml.XmlTextReader.Skip()
                 at System.Configuration.XmlUtil.StrictSkipToNextElement(ExceptionAction action)
                 at System.Configuration.BaseConfigurationRecord.ScanSectionsRecursive(XmlUtil xmlUtil, String parentConfigKey, Boolean inLocation, String locationSubPath, OverrideModeSetting overrideMode, Boolean skipInChildApps)
                 at System.Configuration.BaseConfigurationRecord.ScanSectionsRecursive(XmlUtil xmlUtil, String parentConfigKey, Boolean inLocation, String locationSubPath, OverrideModeSetting overrideMode, Boolean skipInChildApps)
                 at System.Configuration.BaseConfigurationRecord.ScanSections(XmlUtil xmlUtil)
                 at System.Configuration.BaseConfigurationRecord.InitConfigFromFile()
            InnerException: 

*注意:这是从测试应用重新创建的。

我调出 user.config 文件，发现一半不见了。

我预计我们的应用程序由于某种原因突然终止。

这似乎很少见，这是我们与设置交互的方式:

//How we read
Settings settings = Settings.Default;
_ourStaticMemberVariable = settings.OurValue;

//How we save
Settings settings = Settings.Default;
settings.OurValue = "Our Value";
settings.Save();

我们使用它的方式有什么问题吗？这两个调用都有一个 try-catch，其中放置了一些默认值，但这些值需要能够从我们的应用程序中重置。

当处于这种状态时，我们的应用程序无法保存新设置——我也想不出一个好的方法来以编程方式恢复。我不得不手动找到 user.config 并将其删除。

我也试过调用 Settings.Reset() 等，但得到了同样的异常。

关于如何解决这个问题的任何想法？还是我们最好编写自己的设置系统或以其他方式保存持久设置？

编辑:如果您收到 ConfigurationErrorsException，解决方法是从代码中删除该文件。

有人知道如何获取 user.config 文件的完整路径吗？

Answer 1

这是一个不需要您退出应用程序的解决方案，感谢 Jarle (http://www.codeproject.com/Articles/30216/Handling-Corrupt-user-config-Settings?msg=3608682#xx3608682xx)。在早期，在调用设置之前，使用这个

    public static bool CheckSettings()
    {
        var isReset = false;

        try
        {
            ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.PerUserRoamingAndLocal);
        }
        catch (ConfigurationErrorsException ex)
        {
            string filename = string.Empty;
            if (!string.IsNullOrEmpty(ex.Filename))
            {
                filename = ex.Filename;
            }
            else
            {
                var innerEx = ex.InnerException as ConfigurationErrorsException;
                if (innerEx != null && !string.IsNullOrEmpty(innerEx.Filename))
                {
                    filename = innerEx.Filename;
                }                   
            }

            if (!string.IsNullOrEmpty(filename))
            {
                if (System.IO.File.Exists(filename))
                {
                    var fileInfo = new System.IO.FileInfo(filename);
                    var watcher
                         = new System.IO.FileSystemWatcher(fileInfo.Directory.FullName, fileInfo.Name);
                    System.IO.File.Delete(filename);
                    isReset = true;
                    if (System.IO.File.Exists(filename))
                    {
                        watcher.WaitForChanged(System.IO.WatcherChangeTypes.Deleted);
                    }
                }
            }
        }

        return isReset;
    }

本质上，与其依赖 Sittings 来抛出错误，不如使用 ConfigurationManager 读取文件，这样系统的版本就永远不会进入错误状态。