扩展.NET 2.0标准配置文件

以前在看一些开源的项目时，发现它们的Web.config文件都做了扩展，让我很是羡慕，也想用在自己的项目中，于是查阅了一些资料和原码。现在做一个总结，同时也整理出来，与大家一同分享。如您发现什么问题或疑问，欢迎留言。

本文示例代码下载
一、Web.config文件

所有的ASP.NET配置信息都驻留在Web.config文件中的configuration元素中。此元素中的配置信息分为两个主区域：配置节处理程序声明区域（configSections节点中的内容）和配置节设置区域（configSections节点以外的内容）。

配置节处理程序声明区域驻留在Web.config文件中的configSections元素内。它包含在其中声明节处理程序的ASP.NET配置section元素。可以将这些配置节处理程序声明嵌套在sectionGroup元素中，以帮助组织配置信息。通常，sectionGroup元素表示要应用配置设置的命名空间。

配置节设置区域位于配置节处理程序声明区域之后，它包含实际的配置设置。配置节元素还可以包含子元素，这些子元素与其父元素由同一个节处理程序处理。

1:  <?xml version="1.0"?>

2:  <configuration>

3:    <configSections>

4:      <sectionGroup name="CustomConfiguration">

5:        <section name="MyUrls_Declarative" type="Samples.AspNet.Declarative.UrlsSection, CustomConfiguration" />

6:        <section name="MyUrls_Programmatic" type="Samples.AspNet.Programmatic.UrlsSection, CustomConfiguration, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" allowDefinition="Everywhere" allowExeDefinition="MachineToApplication" restartOnExternalChanges="true" />

7:      </sectionGroup>

8:    </configSections>

9:   

10:    <CustomConfiguration>

11:      <MyUrls_Declarative name="MyUrls_Declarative">

12:        <simple name="Microsoft" url="http://www.microsoft.com" port="0" />

13:        <urls>

14:          <clear />

15:          <add name="Microsoft" url="http://www.microsoft.com" port="0" />

16:          <add name="Contoso" url="http://www.contoso.com/" port="8080" />

17:        </urls>

18:      </MyUrls_Declarative>

19:   

20:      <MyUrls_Programmatic name="MyUrls_Programmatic">

21:        <simple name="Microsoft" url="http://www.microsoft.com" port="0" />

22:        <urls>

23:          <clear />

24:          <add name="Microsoft" url="http://www.microsoft.com" port="0" />

25:          <add name="Contoso" url="http://www.contoso.com/" port="8080" />

26:        </urls>

27:      </MyUrls_Programmatic>

28:    </CustomConfiguration>

29:  </configuration>

其中，第10行的CustomConfiguration这个名字要与第4行name中的名字相一致；第11行的MyUrls_Declarative这个名字要与第5行name中的名字相一致；第20行的MyUrls_Programmatic这个名字要与第6行name中的名字相一致。

第5、6行中的type为处理此节点的程序名。

格式为：命名空间.处理的类名，包含这个类的程序集名称（BIN目录下DLL的名称），版本号，文化和公钥。前两项必需，后三项有无。

type="ConfigurationSectionHandlerClass, AssemblyFileName, Version, Culture, PublicKeyToken"

section节点中还可以包括其他一些非必需信息，请参考MSDN。

二、编写处理程序

您可以用自己的XML配置元素来扩展标准的ASP.NET配置设置集。若要完成该操作，您必须创建自己的配置节处理程序。其中配置节处理程序又可分为声明性模型和编程模型。

该处理程序必须是一个用来实现System.Configuration.ConfigurationSection类的.NET Framework类。在.NET Framework 1.0和1.1版中，配置节处理程序必须实现System.Configuration.IConfigurationSectionHandler接口，该接口现在已被否决。

节处理程序解释并处理Web.config文件特定部分中XML配置元素中定义的设置，并根据配置设置返回适当的配置对象。处理程序类返回的配置对象可以是任何数据结构；它不限于任何基配置类或配置格式。ASP.NET使用该配置对象，以对自定义配置元素进行读取和写入。

1、声明性模型处理程序

1:  using System;

2:  using System.Configuration;

3:  using System.Collections;

4:   

5:  namespace Samples.AspNet.Declarative

6:  {

7:      // Define a custom section containing a simple element and a collection of the same element.

8:      // It uses two custom types: UrlsCollection and UrlsConfigElement.[code]   9:      public class UrlsSection : ConfigurationSection

10:      {

11:          [ConfigurationProperty("name", DefaultValue = "MyUrls_Declarative", IsRequired = true, IsKey = false)][/code]
  12:          [StringValidator(InvalidCharacters = " ~!@#$%^&*()[]{}/;'/"|//", MinLength = 1, MaxLength = 60)]
13:          public string Name
14:          {
15:              get
16:              {
17:                  return (string)this["name"];
18:              }
19:              set
20:              {
21:                  this["name"] = value;
22:              }
23:          }
24:   
25:          [ConfigurationProperty("simple")]
26:          public UrlConfigElement Simple
27:          {
28:              get
29:              {
30:                  return (UrlConfigElement)this["simple"];
31:              }
32:          }
33:   
34:          [ConfigurationProperty("urls",IsDefaultCollection = false)]
35:          public UrlsCollection Urls
36:          {
37:              get
38:              {
39:                  return (UrlsCollection)this["urls"];
40:              }
41:          }
42:      }
43:   
44:      // Define the UrlsCollection that contains UrlsConfigElement elements.
45:      public class UrlsCollection : ConfigurationElementCollection
46:      {
47:          protected override ConfigurationElement CreateNewElement()
48:          {
49:              return new UrlConfigElement();
50:          }
51:          protected override Object GetElementKey(ConfigurationElement element)
52:          {
53:              return ((UrlConfigElement)element).Name;
54:          }
55:      }
56:   
57:      // Define the UrlConfigElement.
58:      public class UrlConfigElement : ConfigurationElement
59:      {
60:          [ConfigurationProperty("name", DefaultValue = "Microsoft", IsRequired = true, IsKey = true)]
61:          public string Name
62:          {
63:              get
64:              {
65:                  return (string)this["name"];
66:              }
67:              set
68:              {
69:                  this["name"] = value;
70:              }
71:          }
72:   
73:          [ConfigurationProperty("url", DefaultValue = "http://www.microsoft.com", IsRequired = true)]
74:          [RegexStringValidator(@"/w+:////[/w.]+/S*")]
75:          public string Url
76:          {
77:              get
78:              {
79:                  return (string)this["url"];
80:              }
81:              set
82:              {
83:                  this["url"] = value;
84:              }
85:          }
86:   
87:          [ConfigurationProperty("port", DefaultValue = (int)0, IsRequired = false)]
88:          [IntegerValidator(MinValue = 0, MaxValue = 8080, ExcludeRange = false)]
89:          public int Port
90:          {
91:              get
92:              {
93:                  return (int)this["port"];
94:              }
95:              set
96:              {
97:                  this["port"] = value;
98:              }
99:          }
100:   
101:          public override string ToString()
102:          {
103:              string output = "urls :";
104:              output += string.Format(" name = {0} ", Name);
105:              output += string.Format(" url = {0} ", Url);
106:              output += string.Format(" port = {0} ", Port);
107:              return output;
108:          }
109:      }
110:  }

2、编程模型处理程序

1:  using System;
2:  using System.Configuration;
3:  using System.Collections;
4:  using System.ComponentModel;
5:   
6:  namespace Samples.AspNet.Programmatic
7:  {
8:      // Define a custom section containing a simple element and a collection of the same element.
9:      // It uses two custom types: UrlsCollection and UrlsConfigElement.
10:      public class UrlsSection : ConfigurationSection
11:      {
12:          private static ConfigurationPropertyCollection _Properties;
13:          private static ConfigurationProperty _Name;
14:          private static ConfigurationProperty _Simple;
15:          private static ConfigurationProperty _Urls;
16:   
17:          static UrlsSection()
18:          {
19:              // Initialize the _Name
20:              _Name = new ConfigurationProperty("name", typeof(string), "MyUrls_Programmatic", ConfigurationPropertyOptions.IsRequired);
21:              _Simple = new ConfigurationProperty("simple", typeof(UrlConfigElement));
22:              _Urls = new ConfigurationProperty("urls", typeof(UrlsCollection));
23:   
24:              // Property collection initialization.
25:              // The collection (property bag) that contains the properties is declared as:
26:              // ConfigurationPropertyCollection _Properties;
27:              _Properties = new ConfigurationPropertyCollection();
28:              _Properties.Add(_Name);
29:              _Properties.Add(_Simple);
30:              _Properties.Add(_Urls);
31:          }
32:   
33:          // Return the initialized property bag for the configuration element.
34:          protected override ConfigurationPropertyCollection Properties
35:          {
36:              get
37:              {
38:                  return _Properties;
39:              }
40:          }
41:   
42:          [StringValidator(InvalidCharacters = " ~!@#$%^&*()[]{}/;'/"|//", MinLength = 1, MaxLength = 60)]
43:          public string Name
44:          {
45:              get
46:              {
47:                  return (string)this["name"];
48:              }
49:              set
50:              {
51:                  this["name"] = value;
52:              }
53:          }
54:   
55:          public UrlConfigElement Simple
56:          {
57:              get
58:              {
59:                  return (UrlConfigElement)this["simple"];
60:              }
61:          }
62:   
63:          public UrlsCollection Urls
64:          {
65:              get
66:              {
67:                  return (UrlsCollection)this["urls"];
68:              }
69:          }
70:      }
71:   
72:      // Define the UrlsCollection that contains UrlsConfigElement elements.
73:      public class UrlsCollection : Con
d49c
figurationElementCollection
74:      {
75:          protected override ConfigurationElement CreateNewElement()
76:          {
77:              return new UrlConfigElement();
78:          }
79:          protected override Object GetElementKey(ConfigurationElement element)
80:          {
81:              return ((UrlConfigElement)element).Name;
82:          }
83:      }
84:   
85:      // Define the UrlConfigElement.
86:      public class UrlConfigElement : ConfigurationElement
87:      {
88:          private static ConfigurationPropertyCollection _Properties;
89:          private static ConfigurationProperty _Name;
90:          private static ConfigurationProperty _Url;
91:          private static ConfigurationProperty _Port;
92:   
93:          static UrlConfigElement()
94:          {
95:              // Initialize the _Name
96:              _Name = new ConfigurationProperty("name", typeof(string), "Microsoft", ConfigurationPropertyOptions.IsKey | ConfigurationPropertyOptions.IsRequired);
97:   
98:              ConfigurationValidatorBase _UrlValidator = new RegexStringValidator(@"/w+:////[/w.]+/S*");
99:              _Url = new ConfigurationProperty("url", typeof(string), "http://www.microsoft.com", TypeDescriptor.GetConverter(typeof(string)), _UrlValidator, ConfigurationPropertyOptions.IsRequired);
100:   
101:              ConfigurationValidatorBase _PortValidator = new IntegerValidator(0, 8080);
102:              _Port = new ConfigurationProperty("port", typeof(int), (int)0, null, _PortValidator, ConfigurationPropertyOptions.None);
103:   
104:              // Property collection initialization.
105:              // The collection (property bag) that contains the properties is declared as:
106:              // ConfigurationPropertyCollection _Properties;
107:              _Properties = new ConfigurationPropertyCollection();
108:              _Properties.Add(_Name);
109:              _Properties.Add(_Url);
110:              _Properties.Add(_Port);
111:          }
112:   
113:          // Return the initialized property bag for the configuration element.
114:          protected override ConfigurationPropertyCollection Properties
115:          {
116:              get
117:              {
118:                  return _Properties;
119:              }
120:          }
121:   
122:          public string Name
123:          {
124:              get
125:              {
126:                  return (string)this["name"];
127:              }
128:              set
129:              {
130:                  this["name"] = value;
131:              }
132:          }
133:   
134:          public string Url
135:          {
136:              get
137:              {
138:                  return (string)this["url"];
139:              }
140:              set
141:              {
142:                  this["url"] = value;
143:              }
144:          }
145:   
146:          public int Port
147:          {
148:              get
149:              {
150:                  return (int)this["port"];
151:              }
152:              set
153:              {
154:                  this["port"] = value;
155:              }
156:          }
157:   
158:          public override string ToString()
159:          {
160:              string output = "urls :";
161:              output += string.Format(" name = {0} ", Name);
162:              output += string.Format(" url = {0} ", Url);
163:              output += string.Format(" port = {0} ", Port);
164:              return output;
165:          }
166:      }
167:  }


三、使用

1:      protected void Page_Load(object sender, EventArgs e)
2:      {
3:          Samples.AspNet.Declarative.UrlsSection dus = (Samples.AspNet.Declarative.UrlsSection)ConfigurationManager.GetSection("CustomConfiguration/MyUrls_Declarative");
4:          Response.Write(dus.Name);
5:          Response.Write("<br>");
6:          foreach (Samples.AspNet.Declarative.UrlConfigElement due in dus.Urls)
7:          {
8:              Response.Write(due.ToString());
9:              Response.Write("<br>");
10:          }
11:
12:          Response.Write("<br>");
13:   
14:          Samples.AspNet.Programmatic.UrlsSection pus = (Samples.AspNet.Programmatic.UrlsSection)ConfigurationManager.GetSection("CustomConfiguration/MyUrls_Programmatic");
15:          Response.Write(pus.Name);
16:          Response.Write("<br>");
17:          foreach (Samples.AspNet.Programmatic.UrlConfigElement pue in pus.Urls)
18:          {
19:              Response.Write(pue.ToString());
20:              Response.Write("<br>");
21:          }
22:   
23:      }

上面的代码放在页面代码里。

得到输出：

MyUrls_Declarative
urls : name = Microsoft url = http://www.microsoft.com port = 0
urls : name = Contoso url = http://www.contoso.com/ port = 8080
MyUrls_Programmatic
urls : name = Microsoft url = http://www.microsoft.com port = 0
urls : name = Contoso url = http://www.contoso.com/ port = 8080

好了，到此为止，相信您已经能自己扩展配置文件了，可以看出，使用声明性模型所需要编写的代码稍微少一些，但是在程序取值时需要用到反射，所以如果取舍，就看你了。

参考文章:

MSDN

关于.Net2.0下配置架构的使用

革新：.NET 2.0的自定义配置文件体系初探

.NET 2.0 中的自定义配置处理——编程模型