c# - 在哪里存储将在我的应用程序中使用的常量对象

Question

假设我有一个item，它有字段（属性）

1. 地点
2. 平均值
3. 可用性

而且我有 10-15 items，我想预定义其值，或者将其写入某处，然后加载到要使用的代码中。

哪个是最好的做法？

这些将是常量，只是启动参数，在应用程序生命周期中不会被修改。

Answer 1

List<Item>您可以使用此帮助程序类对 XML 文件进行序列化和反序列化：

public static class XmlHelper
{
    // Specifies whether XML attributes each appear on their own line
    const bool newLineOnAttributes = false;

    public static bool NewLineOnAttributes { get; set; }
    /// <summary>
    /// Serializes an object to an XML string, using the specified namespaces.
    /// </summary>
    public static string ToXml(object obj, XmlSerializerNamespaces ns)
    {
        Type T = obj.GetType();

        var xs = new XmlSerializer(T);
        var ws = new XmlWriterSettings { Indent = true, NewLineOnAttributes = newLineOnAttributes, OmitXmlDeclaration = true };

        var sb = new StringBuilder();
        using (XmlWriter writer = XmlWriter.Create(sb, ws))
        {
            xs.Serialize(writer, obj, ns);
        }
        return sb.ToString();
    }

    /// <summary>
    /// Serializes an object to an XML string.
    /// </summary>
    public static string ToXml(object obj)
    {
        var ns = new XmlSerializerNamespaces();
        ns.Add("", "");
        return ToXml(obj, ns);
    }

    /// <summary>
    /// Deserializes an object from an XML string.
    /// </summary>
    public static T FromXml<T>(string xml)
    {
        XmlSerializer xs = new XmlSerializer(typeof(T));
        using (StringReader sr = new StringReader(xml))
        {
            return (T)xs.Deserialize(sr);
        }
    }

    /// <summary>
    /// Serializes an object to an XML file.
    /// </summary>
    public static void ToXmlFile(Object obj, string filePath)
    {
        var xs = new XmlSerializer(obj.GetType());
        var ns = new XmlSerializerNamespaces();
        var ws = new XmlWriterSettings { Indent = true, NewLineOnAttributes = NewLineOnAttributes, OmitXmlDeclaration = true };
        ns.Add("", "");

        using (XmlWriter writer = XmlWriter.Create(filePath, ws))
        {
            xs.Serialize(writer, obj);
        }
    }

    /// <summary>
    /// Deserializes an object from an XML file.
    /// </summary>
    public static T FromXmlFile<T>(string filePath)
    {
        StreamReader sr = new StreamReader(filePath);
        try
        {
            var result = FromXml<T>(sr.ReadToEnd());
            return result;
        }
        catch (Exception e)
        {
            throw new Exception(e.InnerException.Message);
        }
        finally
        {
            sr.Close();
        }
    }
}

用法：

XmlHelper.ToXmlFile(myList, @"c:\folder\file.xml");

var list = XmlHelper.FromXmlFile<List<Item>>(@"c:\folder\file.xml");

Answer 2

您的选择将是：

1. XML - 实际上是您的标签之一
2. 数据库
3. 二进制文件

存储对象并在您的代码中读取它们。

编写 XML 代码示例：

public void WriteXML()
{
    Book overview = new Book();
    overview.title = "Serialization Overview";
    System.Xml.Serialization.XmlSerializer writer = 
        new System.Xml.Serialization.XmlSerializer(typeof(Book));

    System.IO.StreamWriter file = new System.IO.StreamWriter(
        @"c:\temp\SerializationOverview.xml");
    writer.Serialize(file, overview);
    file.Close();
}

阅读 XML 代码示例：

public void Read(string  fileName)
{
    XDocument doc = XDocument.Load(fileName);

    foreach (XElement el in doc.Root.Elements())
    {
        Console.WriteLine("{0} {1}", el.Name, el.Attribute("id").Value);
        Console.WriteLine("  Attributes:");
        foreach (XAttribute attr in el.Attributes())
            Console.WriteLine("    {0}", attr);
        Console.WriteLine("  Elements:");

        foreach (XElement element in el.Elements())
            Console.WriteLine("    {0}: {1}", element.Name, element.Value);
    }
}

Answer 3

ApplicationSettings非常适合启动常量。

Answer 4

你所描述的听起来像是完美的用例T4

您可以将 T4​​ 模板添加到您的项目中，该模板读取 XML 数据（在 Visual Studio 中的设计时）并使用您的静态内容生成 *.cs 文件。如果您需要修改数据，只需修改 XML 文件并单击Transform All Templates解决方案资源管理器中的按钮。

请记住，如果您需要修改这些内容，这将需要您重新编译和重新部署应用程序。如果是这种情况，那么@Mortalus 提供的解决方案是最好的选择。

Answer 5

我会使用 web.config 并将其存储在应用程序设置区域中，然后创建一个类来读取这些将其作为列表检索。

这是它在 Web 配置和 C# 代码中的外观。

 <appSettings>      
    <add key="location_1" value="123"/>
    <add key="avgValue_1" value="123"/>
    <add key="usability_1" value="123"/>
    <add key="location_2" value="123"/>
    <add key="avgValue_2" value="123"/>
    <add key="usability_2" value="123"/>
    <add key="count" value="2"/>
 </appSettings>

public class SomeClass
{
private string location;
private double avgValue;
private int usability;

public string Location 
{
    get { return location; }
    set { location = value; }
}
public double AvgValue
{
    get { return avgValue; }
    set { avgValue = value; }
}
public int Usability
{
    get { return usability; }
    set { usability = value; }
}
}

public class Config
{
public static List<SomeClass> Items
{
    get
    {
        List<SomeClass> result = new List<SomeClass>();

        for (int i = 1; i <= Convert.ToInt32(WebConfigurationManager.AppSettings["count"]); i++)
        {
            SomeClass sClass = new SomeClass();
            sClass.AvgValue = Convert.ToDouble(WebConfigurationManager.AppSettings["avgValue_" + i.ToString()]);
            sClass.Location = WebConfigurationManager.AppSettings["location_" + i.ToString()];
            sClass.Usability = Convert.ToInt32(WebConfigurationManager.AppSettings["usability_" + i.ToString()]);
        }

        return result;
    }
}

}