揭开.NET 2.0配置隐藏的秘密-技术开发专区

揭开.NET 2.0配置隐藏的秘密

作者：吴秦博客编辑：胡铭娅 2010-03-22 11:43 来源：吴秦博客

正如你看到的，在ASP.NET下访问配置节需要使用System.Web.Configuration.WebConfigurationManager，而不是System.Configuration.ConfigurationManager。检查当前的HttpContext足以确定使用哪个管理器(manager)去获取配置节。还有一个增强，我们对这种模式，使得允许我们可以保存修改。我们知道，必须使用Configuration对象来保存修改，因为管理器(manager)类不提供Save()方法。我们可以在我们的GetSection方法中创建一个Configuration对象，但是最终将缺乏灵活性、效率不高。在最终完全的模式中，我这样做，把Configuration对象作为一个参数：

using System.Web;
using System.Web.Configuration;

public class SomeConfigurationSection
{
    static SomeConfigurationSection()
    {
        // Preparation...
    }

    // Properties...

    #region GetSection Pattern
    // Dictionary to store cached instances of the configuration object
    private static Dictionary<string,
            SomeConfigurationSection> m_sections;

    /// <summary>
    /// Finds a cached section with the specified defined name.
    /// </summary>
    private static SomeConfigurationSection
            FindCachedSection(string definedName)
    {
        if (m_sections == null)
        {
            m_sections = new Dictionary<string,
                             SomeConfigurationSection>();
            return null;
        }

        SomeConfigurationSection section;
        if (m_sections.TryGetValue(definedName, out section))
        {
            return section;
        }

        return null;
    }

    /// <summary>
    /// Adds the specified section to the cache under the defined name.
    /// </summary>
    private static void AddCachedSection(string definedName,
                   SomeConfigurationSection section)
    {
        if (m_sections != null)
            m_sections.Add(definedName, section);
    }

    /// <summary>
    /// Removes a cached section with the specified defined name.
    /// </summary>
    public static void RemoveCachedSection(string definedName)
    {
        m_sections.Remove(definedName);
    }

    /// <summary>
    /// Gets the configuration section using the default element name.
    /// </summary>
    /// <remarks>
    /// If an HttpContext exists, uses the WebConfigurationManager
    /// to get the configuration section from web.config. This method
    /// will cache the instance of this configuration section under the
    /// specified defined name.
    /// </remarks>
    public static SomeConfigurationSection GetSection()
    {
        return GetSection("someConfiguration");
    }

    /// <summary>
    /// Gets the configuration section using the specified element name.
    /// </summary>
    /// <remarks>
    /// If an HttpContext exists, uses the WebConfigurationManager
    /// to get the configuration section from web.config. This method
    /// will cache the instance of this configuration section under the
    /// specified defined name.
    /// </remarks>
    public static SomeConfigurationSection GetSection(string definedName)
    {
        if (String.IsNullOrEmpty(definedName))
            definedName = "someConfiguration";

        SomeConfigurationSection section = FindCachedSection(definedName);
        if (section == null)
        {
            string cfgFileName = ".config";
            if (HttpContext.Current == null)
            {
                section = ConfigurationManager.GetSection(definedName)
                          as SomeConfigurationSection;
            }
            else
            {
                section = WebConfigurationManager.GetSection(definedName)
                          as SomeConfigurationSection;
                cfgFileName = "web.config";
            }

            if (section == null)
                throw new ConfigurationException("The <" + definedName +
                   "> section is not defined in your " + cfgFileName +
                   " file!");

            AddCachedSection(definedName, section);
        }

        return section;
    }

    /// <summary>
    /// Gets the configuration section using the default element name
    /// from the specified Configuration object.
    /// </summary>
    /// <remarks>
    /// If an HttpContext exists, uses the WebConfigurationManager
    /// to get the configuration section from web.config.
    /// </remarks>
    public static SomeConfigurationSection GetSection(Configuration config)
    {
        return GetSection(config, "someConfiguration");
    }

    /// <summary>
    /// Gets the configuration section using the specified element name
    /// from the specified Configuration object.
    /// </summary>
    /// <remarks>
    /// If an HttpContext exists, uses the WebConfigurationManager
    /// to get the configuration section from web.config.
    /// </remarks>
    public static SomeConfigurationSection GetSection(Configuration config,
                                           string definedName)
    {
        if (config == null)
            throw new ArgumentNullException("config",
                  "The Configuration object can not be null.");

        if (String.IsNullOrEmpty(definedName))
            definedName = "someConfiguration";

        SomeConfigurationSection section = config.GetSection(definedName)
                                           as SomeConfigurationSection;

        if (section == null)
            throw new ConfigurationException("The <" + definedName +
                  "> section is not defined in your .config file!");

        return section;
    }
    #endregion
}

关注我们