有没有办法覆盖 ConfigurationManager.AppSettings? [英] Is there a way to override ConfigurationManager.AppSettings?

问题描述

我真的希望能够有一种方法来获取当前使用 ConfigurationManager.AppSettings["mysettingkey"] 获取其设置的应用程序，使这些设置实际上来自中央数据库而不是app.config 文件.我可以制作一个自定义配置部分来处理这类事情，但我真的不希望我团队中的其他开发人员必须更改他们的代码才能使用我的新 DbConfiguration 自定义部分.我只是希望他们能够像往常一样调用 AppSettings，但可以从中央数据库加载.

I really want to be able to have a way to take an app that currently gets its settings using ConfigurationManager.AppSettings["mysettingkey"] to actually have those settings come from a centralized database instead of the app.config file. I can make a custom config section for handling this sort of thing, but I really don't want other developers on my team to have to change their code to use my new DbConfiguration custom section. I just want them to be able to call AppSettings the way they always have but have it be loaded from a central database.

有什么想法吗?

推荐答案

如果您不介意围绕框架进行黑客攻击，并且您可以合理地假设应用程序正在运行的 .net 框架版本(即它是 Web 应用程序或Intranet 应用程序)然后你可以尝试这样的事情:

If you don't mind hacking around the framework and you can reasonably assume the .net framework version the application is running on (i.e. it's a web application or an intranet application) then you could try something like this:

using System;
using System.Collections.Specialized;
using System.Configuration;
using System.Configuration.Internal;
using System.Reflection;

static class ConfigOverrideTest
{
  sealed class ConfigProxy:IInternalConfigSystem
  {
    readonly IInternalConfigSystem baseconf;

    public ConfigProxy(IInternalConfigSystem baseconf)
    {
      this.baseconf = baseconf;
    }

    object appsettings;
    public object GetSection(string configKey)
    {
      if(configKey == "appSettings" && this.appsettings != null) return this.appsettings;
      object o = baseconf.GetSection(configKey);
      if(configKey == "appSettings" && o is NameValueCollection)
      {
        // create a new collection because the underlying collection is read-only
        var cfg = new NameValueCollection((NameValueCollection)o);
        // add or replace your settings
        cfg["test"] = "Hello world";
        o = this.appsettings = cfg;
      }
      return o;
    }

    public void RefreshConfig(string sectionName)
    {
      if(sectionName == "appSettings") appsettings = null;
      baseconf.RefreshConfig(sectionName);
    }

    public bool SupportsUserConfig
    {
      get { return baseconf.SupportsUserConfig; }
    }
  }

  static void Main()
  {
    // initialize the ConfigurationManager
    object o = ConfigurationManager.AppSettings;
    // hack your proxy IInternalConfigSystem into the ConfigurationManager
    FieldInfo s_configSystem = typeof(ConfigurationManager).GetField("s_configSystem", BindingFlags.Static | BindingFlags.NonPublic);
    s_configSystem.SetValue(null, new ConfigProxy((IInternalConfigSystem)s_configSystem.GetValue(null)));
    // test it
    Console.WriteLine(ConfigurationManager.AppSettings["test"] == "Hello world" ? "Success!" : "Failure!");
  }
}

这篇关于有没有办法覆盖 ConfigurationManager.AppSettings?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！