揭开.NET 2.0配置隐藏的秘密
5、添加自定义元素
默认情况下，自定义配置节中所有的配置属性(properties)在.config文件中被表示成属性(attributes)。这并不总是必然的，然而，一个更复杂XML结构，由属性(attributes)和元素(elements)混合组成的，是需要的。不要怕：.NET的配置系统完全支持自定义配置元素，他们的属性(properties)可以是属性(attributes)或者多个嵌套元素。要创建自定义配置元素，简单地写一个类继承自ConfigurationElement而不是ConfigurationSection。配置元素的执行细节跟配置节一样，不同之处是元素必须嵌套在配置节中。
让我们继续，嵌套一个自定义元素在ExampleSection中。让我们这个嵌套元素存储一个DateTime值和一个整数值。创建这个类的代码如下所示：
using System;
using System.Configuration;
#endregion
namespace Examples.Configuration
{
///
/// An example configuration element class.
///
public class NestedElement: ConfigurationElement
{
#region Constructors
///
/// Predefines the valid properties and prepares
/// the property collection.
///
static NestedElement()
{
// Predefine properties here
s_propDateTime = new ConfigurationProperty(
"dateTimeValue",
typeof(DateTime),
null,
ConfigurationPropertyOptions.IsRequired
);
s_propInteger = new ConfigurationProperty(
"integerValue",
typeof(int),
0,
ConfigurationPropertyOptions.IsRequired
);
s_properties = new ConfigurationPropertyCollection();
s_properties.Add(s_propDateTime);
s_properties.Add(s_propInteger);
}
#endregion
#region Static Fields
private static ConfigurationProperty s_propDateTime;
private static ConfigurationProperty s_propInteger;
private static ConfigurationPropertyCollection s_properties;
#endregion
#region Properties
///
/// Gets the DateTimeValue setting.
///
[ConfigurationProperty("dateTimeValue", IsRequired=true)]
public DateTime StringValue
{
get { return (DateTime)base[s_propDateTime]; }
}
///
/// Gets the IntegerValue setting.
///
[ConfigurationProperty("integerValue")]
public int IntegerValue
{
get { return (int)base[s_propInteger]; }
}
///
/// Override the Properties collection and return our custom one.
///
protected override ConfigurationPropertyCollection Properties
{
get { return s_properties; }
}
#endregion
}
using System.Configuration;
#endregion
namespace Examples.Configuration
{
///
/// An example configuration element class.
///
public class NestedElement: ConfigurationElement
{
#region Constructors
///
/// Predefines the valid properties and prepares
/// the property collection.
///
static NestedElement()
{
// Predefine properties here
s_propDateTime = new ConfigurationProperty(
"dateTimeValue",
typeof(DateTime),
null,
ConfigurationPropertyOptions.IsRequired
);
s_propInteger = new ConfigurationProperty(
"integerValue",
typeof(int),
0,
ConfigurationPropertyOptions.IsRequired
);
s_properties = new ConfigurationPropertyCollection();
s_properties.Add(s_propDateTime);
s_properties.Add(s_propInteger);
}
#endregion
#region Static Fields
private static ConfigurationProperty s_propDateTime;
private static ConfigurationProperty s_propInteger;
private static ConfigurationPropertyCollection s_properties;
#endregion
#region Properties
///
/// Gets the DateTimeValue setting.
///
[ConfigurationProperty("dateTimeValue", IsRequired=true)]
public DateTime StringValue
{
get { return (DateTime)base[s_propDateTime]; }
}
///
/// Gets the IntegerValue setting.
///
[ConfigurationProperty("integerValue")]
public int IntegerValue
{
get { return (int)base[s_propInteger]; }
}
///
/// Override the Properties collection and return our custom one.
///
protected override ConfigurationPropertyCollection Properties
{
get { return s_properties; }
}
#endregion
}
自定义配置元素类#region Using Statements
0
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