将自定义属性添加到app.config中的Custom Provider Configuration Section

Question

我正在关注如何在.NET中创建Provider框架的这篇伟大文章

基本上,本文大致解释了如何最终得到如下配置文件:

   <configuration>
     <configSections>
        <section name="data" type="DataProviderConfigurationSection" />
      </configSections>
      <data defaultProvider="MyDataProvider">
         <providers>
            <add name="MydataProvider" type="MyDataProvider"  />
         </providers>
      </data>
   </configuration>

凡<add/>元素允许你定义一个供应商.

但是,我想知道如何add使用自定义属性扩展条目.

例如:

<providers>
  <add name="MydataProvider" type="MyDataProvider" myProperty="myValue" myProperty2="myValue2" ... />
</providers>

任何帮助将不胜感激.

Answer 1

这是我终于找到的.这是一个非常具体的问题,关于扩展具有更多属性的元素以及在实现Provider Framework时如何处理它们.关于自定义配置部分的所有答案都可以,但不能解决原始问题.

如果您需要实现自定义提供程序,例如MembershipProvider,但出于您自己的目的,您需要阅读本文:创建自己的提供程序框架

这是很好的阅读.现在,如果您需要使用自己的属性扩展元素,那么您需要更改...

1)接下来是文章中讨论的代码(可能有一些改编):

using System;
using System.Configuration;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Configuration.Provider;
using System.Collections.Specialized;


    public abstract class DataProvider : ProviderBase
    {
        // Define the methods to be used by the provider.  These are custom methods to your own provider.
        public abstract void Get();
        public abstract void Delete();
    }

    public class DataProviderCollection : ProviderCollection { }




    //The name is typically the same as the abstract class, minus the Provider part. Sticking to our (fake) example. we'd have a static class called Data.
    public static class Data
    {
        private static bool _isInitialized = false;

        private static DataProvider _provider;
        public static DataProvider Provider
        {
            get
            {
                Initialize();
                return _provider;
            }
        }

        private static DataProviderCollection _providers;
        public static DataProviderCollection Providers
        {
            get
            {
                Initialize();
                return _providers;
            }
        }

        private static void Initialize()
        {
            DataProviderConfigurationSection dataConfig = null;

            if (!_isInitialized)
            {
                // get the configuration section for the feature
                dataConfig = (DataProviderConfigurationSection)ConfigurationManager.GetSection("data");

                if (dataConfig == null)
                {
                    throw new ConfigurationErrorsException("Data is not configured to be used with this application");
                }

                _providers = new DataProviderCollection();

                // use the ProvidersHelper class to call Initialize() on each provider
                ProvidersHelper.InstantiateProviders(dataConfig.Providers, _providers, typeof(DataProvider));

                // set a reference to the default provider
                _provider = _providers[dataConfig.DefaultProvider] as DataProvider;

                _isInitialized = true;
            }
        }

        public static void Get()
        {
            Initialize();
            if (_provider != null)
            {
                _provider.Get();
            }
        }

        public static void Delete()
        {
            Initialize();
            if (_provider != null)
            {
                _provider.Delete();
            }
        }
    }

    public class MyDataProvider : DataProvider
    {




        public override void Get()
        {
            // Get Code
        }

        public override void Delete()
        {
            // Delete Code
        }
    }

    public class DataProviderConfigurationSection : ConfigurationSection
    {
        public DataProviderConfigurationSection()
        {
            _defaultProvider = new ConfigurationProperty("defaultProvider", typeof(string), null);
            _providers = new ConfigurationProperty("providers", typeof(ProviderSettingsCollection), null);
            _properties = new ConfigurationPropertyCollection();

            _properties.Add(_providers);
            _properties.Add(_defaultProvider);
        }

        private readonly ConfigurationProperty _defaultProvider;
        [ConfigurationProperty("defaultProvider")]
        public string DefaultProvider
        {
            get { return (string)base[_defaultProvider]; }
            set { base[_defaultProvider] = value; }
        }

        private readonly ConfigurationProperty _providers;
        [ConfigurationProperty("providers")]
        public ProviderSettingsCollection Providers
        {
            get { return (ProviderSettingsCollection)base[_providers]; }
        }

        private ConfigurationPropertyCollection _properties;
        protected override ConfigurationPropertyCollection Properties
        {
            get { return _properties; }
        }
    }

    public static class ProvidersHelper
    {
        private static Type providerBaseType = typeof(ProviderBase);

        /// <summary>
        /// Instantiates the provider.
        /// </summary>
        /// <param name="providerSettings">The settings.</param>
        /// <param name="providerType">Type of the provider to be instantiated.</param>
        /// <returns></returns>
        public static ProviderBase InstantiateProvider(ProviderSettings providerSettings, Type providerType)
        {
            ProviderBase base2 = null;
            try
            {
                string str = (providerSettings.Type == null) ? null : providerSettings.Type.Trim();
                if (string.IsNullOrEmpty(str))
                {
                    throw new ArgumentException("Provider type name is invalid");
                }
                Type c = Type.GetType(str, true, true);
                if (!providerType.IsAssignableFrom(c))
                {
                    throw new ArgumentException(String.Format("Provider must implement type {0}.", providerType.ToString()));
                }
                base2 = (ProviderBase)Activator.CreateInstance(c);
                NameValueCollection parameters = providerSettings.Parameters;
                NameValueCollection config = new NameValueCollection(parameters.Count, StringComparer.Ordinal);
                foreach (string str2 in parameters)
                {
                    config[str2] = parameters[str2];
                }
                base2.Initialize(providerSettings.Name, config);
            }
            catch (Exception exception)
            {
                if (exception is ConfigurationException)
                {
                    throw;
                }
                throw new ConfigurationErrorsException(exception.Message,
                    providerSettings.ElementInformation.Properties["type"].Source,
                    providerSettings.ElementInformation.Properties["type"].LineNumber);
            }
            return base2;
        }

        public static void InstantiateProviders(ProviderSettingsCollection providerSettings, ProviderCollection providers, Type type)
        {
            foreach (ProviderSettings settings in providerSettings)
            {
                providers.Add(ProvidersHelper.InstantiateProvider(settings, type));
            }
        }
    }

2)这是您用于上述代码的配置文件:

  <configuration>
    <configSections>
      <section name="data" type="DataProviderConfigurationSection" />
    </configSections>
    <data defaultProvider="MyDataProvider">
      <providers>
        <add name="MydataProvider" type="MyDataProvider"  />
      </providers>
    </data>
  </configuration>

3)现在,您需要修改以便使用读取<add>配置文件中元素的属性.

    public abstract class DataProvider : ProviderBase
    {

        public string MyAttribute1 { get; set; }
        public string MyAttribute2 { get; set; }
        public string MyAttribute3 { get; set; }

        // Define the methods to be used by the provider.  These are custom methods to your own provider.
        public abstract void Get();
        public abstract void Delete();

        public override void Initialize(string name, NameValueCollection config)
        {

            MyAttribute1 = config["MyAttribute1"];
            MyAttribute2 = config["MyAttribute2"];
            MyAttribute3 = config["MyAttribute3"];

            base.Initialize(name, config);
        }
    }

4)配置文件如下所示:

  <configuration>
    <configSections>
      <section name="data" type="DataProviderConfigurationSection" />
    </configSections>
    <data defaultProvider="MyDataProvider">
      <providers>
        <add name="MydataProvider" type="MyDataProvider" MyAttribute1="MyValue1" MyAttribute2="MyValue2"   />
      </providers>
    </data>
  </configuration>

作为奖励,这里有一个单元测试来验证它的工作原理:

[TestMethod]
public void RunMyDataProviderTest()
        {
            DataProvider dataProvider = Data.Provider;

            Assert.IsInstanceOfType(dataProvider, typeof(MyDataProvider));

            Assert.AreEqual(dataProvider.MyAttribute1, "MyValue1");
            Assert.AreEqual(dataProvider.MyAttribute2, "MyValue2");
}