我如何使用的后代元素.NET自定义的ConfigurationElement属性？ [英] How do I use .NET custom ConfigurationElement properties on descendent elements?
问题描述
我如何获得并使用在后代CustomSetting元素的父配置节设置属性？我需要的时候CustomSetting元素返回Value属性这个属性。
我想格式化App.config中是这样的：
＆LT; CustomSettings someProperty =富＆GT;
＆LT; CustomSetting键=栏值=fermeneba/＆GT;
＆LT; CustomSetting键=左心耳值=jubaduba/＆GT;
＆LT; / CustomSettings＆GT;
我有code的工作，但我不能找到一种方法，从CustomSetting类访问someProperty属性。我发现的唯一方法，到目前为止，是格式化这样的结构，这是混乱的：
＆LT; CustomSettings＆GT;
＆LT; CustomSetting someProperty =富键=栏值=fermeneba/＆GT;
＆LT; CustomSetting someProperty =富键=左心耳值=jubaduba/＆GT;
＆LT; / CustomSettings＆GT;
实现，这是更困难比它应该是因为System.Configuration API不允许您从导航的ConfigurationElement 其父。因此，如果您要访问的一些信息，一个父元素，你需要手动创建关系。我已经把一个样本实现，它对于你的问题的配置片断：
公共类CustomSettingsSection：配置节
{
[的ConfigurationProperty（someProperty，默认值=）]
公共字符串SomeProperty
{
{返回（串）基地[someProperty]; }
集合{基地[someProperty] =值; }
}
[的ConfigurationProperty（，IsDefaultCollection =真）
公共CustomSettingElementCollection元素
{
得到
{
VAR元素=基地（）作为CustomSettingElementCollection;
如果（元素= NULL和放大器;！＆安培; elements.Section == NULL）
elements.Section =这一点;
返回元素;
}
}
}
公共类CustomSettingElementCollection：ConfigurationElementCollection
{
内部CustomSettingsSection科{获得;组; }
公众覆盖ConfigurationElementCollectionType CollectionType
{
{返回ConfigurationElementCollectionType.BasicMap; }
}
公共CustomSettingElement此[字符串键]
{
{返回BaseGet（键）为CustomSettingElement; }
}
保护覆盖的ConfigurationElement CreateNewElement（）
{
返回新CustomSettingElement {父=这};
}
保护覆盖对象GetElementKey（的ConfigurationElement元）
{
返回（元素CustomSettingElement）。重点;
}
保护覆盖字符串的ElementName
{
{返回customSetting; }
}
}
公共类CustomSettingElement：的ConfigurationElement
{
内部CustomSettingElementCollection家长{获得;组; }
公共字符串SomeProperty
{
得到
{
如果（家长= NULL和放大器;！＆安培;！Parent.Section = NULL）
返回Parent.Section.SomeProperty;
返回默认值（字符串）;
}
}
[的ConfigurationProperty（钥匙，IsKey = TRUE，IsRequired =真）
公共字符串键
{
{返回（串）基地[钥匙]。 }
集合{基地[钥匙] =价值; }
}
[的ConfigurationProperty（价值，默认值=）]
公共字符串值
{
{返回（串）基地[值]; }
集合{基地[值] =值; }
}
}
您可以看到 CustomSettingElementCollection 有一个科属性，它得到了部分的 CustomSettingElement ，反过来，有一个父属性，该属性获取集合的 CreateNewElement设置（ ）方法。
这则使得可以走了关系树到 SomeProperty 属性添加到元素，即使这一个不符合实际的ConfigurationProperty上元素。
希望给你一个想法如何解决您的问题！
How can I get and use an attribute set in the parent ConfigurationSection in the descendent CustomSetting element? I need this attribute when the CustomSetting element is returning the Value property.
I want to format the App.config like this:
<CustomSettings someProperty="foo">
<CustomSetting key="bar" value="fermeneba" />
<CustomSetting key="laa" value="jubaduba" />
</CustomSettings>
I have the code working, except that I cannot find a way to access the someProperty attribute from the CustomSetting class. The only way that I've found, so far, is to format the configuration like this, which is messy:
<CustomSettings>
<CustomSetting someProperty="foo" key="bar" value="fermeneba" />
<CustomSetting someProperty="foo" key="laa" value="jubaduba" />
</CustomSettings>
Achieving this is more difficult than it should be since the System.Configuration API doesn't allow you to navigate from a ConfigurationElement to its parent. Hence, if you want to access some information that on a parent element you need to create that relationship manually. I've put together a sample implementation that does that for the config snippet in your question:
public class CustomSettingsSection : ConfigurationSection
{
[ConfigurationProperty("someProperty", DefaultValue="")]
public string SomeProperty
{
get { return (string)base["someProperty"]; }
set { base["someProperty"] = value; }
}
[ConfigurationProperty("", IsDefaultCollection = true)]
public CustomSettingElementCollection Elements
{
get
{
var elements = base[""] as CustomSettingElementCollection;
if (elements != null && elements.Section == null)
elements.Section = this;
return elements;
}
}
}
public class CustomSettingElementCollection : ConfigurationElementCollection
{
internal CustomSettingsSection Section { get; set; }
public override ConfigurationElementCollectionType CollectionType
{
get { return ConfigurationElementCollectionType.BasicMap; }
}
public CustomSettingElement this[string key]
{
get { return BaseGet(key) as CustomSettingElement; }
}
protected override ConfigurationElement CreateNewElement()
{
return new CustomSettingElement { Parent = this };
}
protected override object GetElementKey(ConfigurationElement element)
{
return (element as CustomSettingElement).Key;
}
protected override string ElementName
{
get { return "customSetting"; }
}
}
public class CustomSettingElement : ConfigurationElement
{
internal CustomSettingElementCollection Parent { get; set; }
public string SomeProperty
{
get
{
if (Parent != null && Parent.Section != null)
return Parent.Section.SomeProperty;
return default(string);
}
}
[ConfigurationProperty("key", IsKey = true, IsRequired = true)]
public string Key
{
get { return (string)base["key"]; }
set { base["key"] = value; }
}
[ConfigurationProperty("value", DefaultValue = "")]
public string Value
{
get { return (string)base["value"]; }
set { base["value"] = value; }
}
}
You can see that the CustomSettingElementCollection has a Section property which gets set in the section's Elements getter. The CustomSettingElement, in turn, has a Parent property which gets set in the collection's CreateNewElement() method.
That then makes it possible to walk up the relationship tree and to add a SomeProperty property to the element even though this one doesn't correspond to an actual ConfigurationProperty on that element.
Hope that gives you an idea how to solve your problem!
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