C# 轻松地将整个类实例写入 XML 文件并读回

Easily write a whole class instance to XML File and read back in

提问by developer__c

I have a main class called theGarage, which contains instances of our customer, supplier, and jobs classes.

我有一个名为 的主类theGarage，其中包含我们的客户、供应商和工作类的实例。

I want to save the program data to an XML file, I have used the code below (just a snippet, I have matching code for the other classes). I am wondering if there is an easier way for me to do this, like write the whole theGarage class to an XML file and read it in without having to write all this code like I have below.

我想将程序数据保存到一个 XML 文件中，我使用了下面的代码（只是一个片段，我有其他类的匹配代码）。我想知道是否有更简单的方法来执行此操作，例如将整个 theGarage 类写入 XML 文件并读取它，而无需像下面那样编写所有这些代码。

   public void saveToFile()
    {
        using (XmlWriter writer = XmlWriter.Create("theGarage.xml"))
        {
            writer.WriteStartDocument();

            ///
            writer.WriteStartElement("theGarage");
            writer.WriteStartElement("Customers");

            foreach (Customer Customer in Program.theGarage.Customers)
            {
                writer.WriteStartElement("Customer");
                writer.WriteElementString("FirstName", Customer.FirstName);
                writer.WriteElementString("LastName", Customer.LastName);
                writer.WriteElementString("Address1", Customer.Address1);
                writer.WriteElementString("Address2", Customer.Address2);
                writer.WriteElementString("Town", Customer.Town);
                writer.WriteElementString("County", Customer.County);
                writer.WriteElementString("PostCode", Customer.Postcode);
                writer.WriteElementString("TelephoneHome", Customer.TelephoneHome);
                writer.WriteElementString("TelephoneMob", Customer.TelephoneMob);

                //begin vehicle list
                writer.WriteStartElement("Vehicles");

                foreach (Vehicle Vehicle in Customer.Cars)
                {
                    writer.WriteStartElement("Vehicle");
                    writer.WriteElementString("Make", Vehicle.Make);
                    writer.WriteElementString("Model", Vehicle.Model);
                    writer.WriteElementString("Colour", Vehicle.Colour);
                    writer.WriteElementString("EngineSize", Vehicle.EngineSize);
                    writer.WriteElementString("Registration", Vehicle.Registration);
                    writer.WriteElementString("Year", Vehicle.YearOfFirstReg);
                    writer.WriteEndElement();
                }
                writer.WriteEndElement();
                writer.WriteEndElement();
            }
        }
    }

采纳答案by Michal Klouda

There is much simpler way of serializing objects, use XmlSerializerinstead. See documentation here.

序列化对象有更简单的方法，请XmlSerializer改用。请参阅此处的文档。

Code snippet to serialize your garage to file could look like:

将车库序列化为文件的代码片段可能如下所示：

var garage = new theGarage();

// TODO init your garage..

XmlSerializer xs = new XmlSerializer(typeof(theGarage));
TextWriter tw = new StreamWriter(@"c:\temp\garage.xml");
xs.Serialize(tw, garage);

And code to load garage from file:

以及从文件加载车库的代码：

using(var sr = new StreamReader(@"c:\temp\garage.xml"))
{
   garage = (theGarage)xs.Deserialize(sr);
}

回答by Richard Friend

What about a couple of nifty extension methods, then you can easily read/write this to/from file.

几个漂亮的扩展方法怎么样，然后您可以轻松地将其读/写到/从文件中。

public static class Extensions
{
    public static string ToXml(this object obj)
    {
        XmlSerializer s = new XmlSerializer(obj.GetType());
        using (StringWriter writer = new StringWriter())
        {
            s.Serialize(writer, obj);
            return writer.ToString();
        }
    }

    public static T FromXml<T>(this string data)
    {
        XmlSerializer s = new XmlSerializer(typeof(T));
        using (StringReader reader = new StringReader(data))
        {
            object obj = s.Deserialize(reader);
            return (T)obj;
        }
    }
}

example

例子

 var xmlData = myObject.ToXml();

 var anotherObject = xmlData.FromXml<ObjectType>();

回答by Rafal

For my project I use DataContractSerializer. I contrast to XmlSerializerit can handle multiple references to the same object in such a manner that data is not duplicated in xml and restored as saved.

对于我的项目，我使用DataContractSerializer。与XmlSerializer相比，它可以处理对同一对象的多个引用，这样数据就不会在 xml 中重复并在保存时恢复。

回答by deadlydog

I just wrote a blog post on saving an object's data to Binary, XML, or Json. Here is the functions to write and read the class instance to/from XML. See my blog post for more details.

我刚刚写了一篇关于将对象数据保存为 Binary、XML 或 Json 的博客文章。下面是向/从 XML 写入和读取类实例的函数。有关更多详细信息，请参阅我的博客文章。

Requires the System.Xml assembly to be included in your project.

需要将 System.Xml 程序集包含在您的项目中。

/// <summary>
/// Writes the given object instance to an XML file.
/// <para>Only Public properties and variables will be written to the file. These can be any type though, even other classes.</para>
/// <para>If there are public properties/variables that you do not want written to the file, decorate them with the [XmlIgnore] attribute.</para>
/// <para>Object type must have a parameterless constructor.</para>
/// </summary>
/// <typeparam name="T">The type of object being written to the file.</typeparam>
/// <param name="filePath">The file path to write the object instance to.</param>
/// <param name="objectToWrite">The object instance to write to the file.</param>
/// <param name="append">If false the file will be overwritten if it already exists. If true the contents will be appended to the file.</param>
public static void WriteToXmlFile<T>(string filePath, T objectToWrite, bool append = false) where T : new()
{
    TextWriter writer = null;
    try
    {
        var serializer = new XmlSerializer(typeof(T));
        writer = new StreamWriter(filePath, append);
        serializer.Serialize(writer, objectToWrite);
    }
    finally
    {
        if (writer != null)
            writer.Close();
    }
}

/// <summary>
/// Reads an object instance from an XML file.
/// <para>Object type must have a parameterless constructor.</para>
/// </summary>
/// <typeparam name="T">The type of object to read from the file.</typeparam>
/// <param name="filePath">The file path to read the object instance from.</param>
/// <returns>Returns a new instance of the object read from the XML file.</returns>
public static T ReadFromXmlFile<T>(string filePath) where T : new()
{
    TextReader reader = null;
    try
    {
        var serializer = new XmlSerializer(typeof(T));
        reader = new StreamReader(filePath);
        return (T)serializer.Deserialize(reader);
    }
    finally
    {
        if (reader != null)
            reader.Close();
    }
}

Example

例子

// Write the list of salesman objects to file.
WriteToXmlFile<Customer>("C:\TheGarage.txt", customer);

// Read the list of salesman objects from the file back into a variable.
Customer customer = ReadFromXmlFile<Customer>("C:\TheGarage.txt");