在C＃中读取xml文件的节点 [英] Read nodes of a xml file in C#

问题描述

如何将以下xml文件读入列表：

How can I read the following xml file into a List:

部分XML文件（data.log）

Partial XML file (data.log)

<ApplicationLogEventObject>
    <EventType>Message</EventType>
    <DateStamp>10/13/2016 11:15:00 AM</DateStamp>
    <ShortDescription>N/A</ShortDescription>
    <LongDescription>Sending 'required orders' email.</LongDescription>
</ApplicationLogEventObject>
<ApplicationLogEventObject>
    <EventType>Message</EventType>
    <DateStamp>10/13/2016 11:15:10 AM</DateStamp>
    <ShortDescription>N/A</ShortDescription>
    <LongDescription>Branches Not Placed Orders - 1018</LongDescription>
</ApplicationLogEventObject>
<ApplicationLogEventObject>
    <EventType>Message</EventType>
    <DateStamp>10/13/2016 11:15:10 AM</DateStamp>
    <ShortDescription>N/A</ShortDescription>
    <LongDescription>Branches Not Placed Orders - 1019</LongDescription>
</ApplicationLogEventObject>
...

这是数据访问层（DAL）：

And here is the data access layer (DAL):

public List<FLM.DataTypes.ApplicationLogEventObject> Get()
    {
        try
        {
            XmlTextReader xmlTextReader = new XmlTextReader(@"C:\data.log");
        List<FLM.DataTypes.ApplicationLogEventObject> recordSet = new List<ApplicationLogEventObject>();

        xmlTextReader.Read();

        while (xmlTextReader.Read())
        {
            xmlTextReader.MoveToElement();
            FLM.DataTypes.ApplicationLogEventObject record = new ApplicationLogEventObject();

            record.EventType = xmlTextReader.GetAttribute("EventType").ToString();
            record.DateStamp = Convert.ToDateTime(xmlTextReader.GetAttribute("DateStamp"));
            record.ShortDescription = xmlTextReader.GetAttribute("ShortDescription").ToString()                    
            record.LongDescription = xmlTextReader.GetAttribute("LongDescription").ToString();

            recordSet.Add(record);
        }
        return recordSet;
    }
    catch (Exception ex)
    {
        throw ex;
    }
}

和数据类型它将保存XML文件中的子元素：

And the Data Types which will hold the child elements from the XML file:

public class ApplicationLogEventObject
{
    public string EventType { get; set; }
    public DateTime DateStamp { get; set; }
    public string ShortDescription { get; set; }
    public string LongDescription { get; set; }
}

将子节点读入列表后，我想返回并显示在DataGridView中。

After I've read the child nodes into a List I would then like to return it and display it in a DataGridView.

有关此问题的任何帮助将不胜感激。

Any help regarding this question will be much appreciated.

推荐答案

您的日志文件不是XML文档。由于XML文档必须只有一个根元素，因此它是一系列XML文档的串联一起。可以通过 XmlReader 通过设置 XmlReaderSettings.ConformanceLevel == ConformanceLevel.Fragment 。这样做后，您可以使用 XmlSerializer 如下：

Your log file is not an XML document. Since an XML document must have one and only one root element, it's a series of XML documents concatenated together. Such a series of documents can be read by XmlReader by setting XmlReaderSettings.ConformanceLevel == ConformanceLevel.Fragment. Having done so, you can read through the file and deserialize each root element individually using XmlSerializer as follows:

static List<ApplicationLogEventObject> ReadEvents(string fileName)
{
    return ReadObjects<ApplicationLogEventObject>(fileName);
}

static List<T> ReadObjects<T>(string fileName)
{
    var list = new List<T>();

    var serializer = new XmlSerializer(typeof(T));
    var settings = new XmlReaderSettings { ConformanceLevel = ConformanceLevel.Fragment };
    using (var textReader = new StreamReader(fileName))
    using (var xmlTextReader = XmlReader.Create(textReader, settings))
    {
        while (xmlTextReader.Read())
        {   // Skip whitespace
            if (xmlTextReader.NodeType == XmlNodeType.Element) 
            {
                using (var subReader = xmlTextReader.ReadSubtree())
                {
                    var logEvent = (T)serializer.Deserialize(subReader);
                    list.Add(logEvent);
                }
            }
        }
    }

    return list;            
}

使用以下版本的 ApplicationLogEventObject ：

public class ApplicationLogEventObject
{
    public string EventType { get; set; }

    [XmlElement("DateStamp")]
    public string DateStampString { 
        get
        {
            // Replace with culturally invariant desired formatting.
            return DateStamp.ToString(CultureInfo.InvariantCulture);
        }
        set
        {
            DateStamp = Convert.ToDateTime(value, CultureInfo.InvariantCulture);
        }
    }

    [XmlIgnore]
    public DateTime DateStamp { get; set; }

    public string ShortDescription { get; set; }
    public string LongDescription { get; set; }
}

样本。Net小提琴。

注意：

• < DateStamp> 元素值 2016/10/13上午11:15:00 对于XML中的日期和时间格式不正确，即 ISO 8601 。因此，我引入了一个代理 string DateStampString 属性来手动处理所需格式的转换，然后标记原始的 DateTime 具有 XmlIgnore 。

• The <DateStamp> element values 10/13/2016 11:15:00 AM are not in the correct format for dates and times in XML, which is ISO 8601. Thus I introduced a surrogate string DateStampString property to manually handle the conversion from and to your desired format, and then marked the original DateTime property with XmlIgnore.

使用 ReadSubtree（） 防止读取超过每个根元素末尾的可能性

Using ReadSubtree() prevents the possibility of reading past the end of each root element when the XML is not indented.

根据文档，用于 XmlTextReader ：

从.NET Framework 2.0开始，建议您改用System.Xml.XmlReader类。

Starting with the .NET Framework 2.0, we recommend that you use the System.Xml.XmlReader class instead.

因此，我建议将这种类型的使用替换为 XmlReader 。

Thus I recommend replacing use of that type with XmlReader.

< ApplicationLogEventObject> 的子节点是元素而不是属性，因此 XmlReader.GetAttribute（） 不是用于读取它们的合适方法。

The child nodes of your <ApplicationLogEventObject> are elements not attributes, so XmlReader.GetAttribute() was not an appropriate method to use to read them.

鉴于您的日志文件未按照ISO 8601格式设置时间，因此至少应确保将其格式设置为文化上不变的格式，以便可以在具有不同区域性的计算机之间交换日志文件设置。使用 CultureInfo进行转换。 InvariantCulture 确保了这一点。

Given that your log files are not formatting their times in ISO 8601, you should at least make sure they are formatted in a culturally invariant format so that log files can be exchanged between computers with different regional settings. Doing your conversions using CultureInfo.InvariantCulture ensures this.

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