c# - 包含子元素集合的配置元素

Question

我想在我的 web.config 中有一个自定义部分，如下所示：

<MyMainSection attributeForMainSection = "value foo">

    <add name = "foo" 
    type = "The.System.Type.Of.Foo, Assembly, Qualified Name Type Name" />

    <add name = "bar" 
    type = "The.System.Type.Of.Bar, Assembly, Qualified Name Type Name" />

</MyMainSection>

我已经定义了以下代码：

using System.Configuration;

class MyMainSection : ConfigurationSection
{
    /*I've provided custom implemenation. 
      Not including it here for the sake of brevity. */ 
    [ConfigurationProperty("attributeForMainSection")]
    public string AttributeForMyMainSection { get; set; }

    [ConfigurationProperty("add")]
    public AddElement TheAddElement { get; set; }

    private class AddElement: ConfigurationElement
    {
        /* Implementation done */
    }

}

如果我想允许多个添加元素，这个属性TheAddElement应该是IEnumerable<AddElement>还是只是？AddElement

Answer 1

也不是，你会引入一个新的ConfigurationCollectionElement例如

部分

class MyMainSection : ConfigurationSection
{
    [ConfigurationProperty("", IsRequired=true, IsDefaultCollection=true)]
    public AddElementCollection Instances 
    {
        get { return (AddElementCollection) this[""]; }
        set { this[""] = value; }
    }
}

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public class AddElementCollection : ConfigurationElementCollection 
{
    protected override ConfigurationElement CreateNewElement() 
    {
        return new AddElement();
    }

    protected override object GetElementKey(ConfigurationElement element) {
        return ((AddElement) element).Name;
    }
}

元素

private class AddElement: ConfigurationElement
{
    [ConfigurationProperty("name", IsKey=true, IsRequired=true)]
    public string Name 
    {
        get { return (string) base["name"]; }
        set { base["name"] = value; 
    }
    ...
}

Answer 2

使用ConfigurationElementCollection处理 ConfigurationElement 对象的集合。实现此类以将自定义 ConfigurationElement 元素的集合添加到 ConfigurationSection：

// Define a custom section that contains a custom 
// UrlsCollection collection of custom UrlConfigElement elements. 
// This class shows how to use the ConfigurationCollectionAttribute. 
public class UrlsSection : ConfigurationSection
{
    // Declare the Urls collection property using the 
    // ConfigurationCollectionAttribute. 
    // This allows to build a nested section that contains 
    // a collection of elements.
    [ConfigurationProperty("urls", IsDefaultCollection = false)]
    [ConfigurationCollection(typeof(UrlsCollection),
        AddItemName = "add",
        ClearItemsName = "clear",
        RemoveItemName = "remove")]
    public UrlsCollection Urls
    {
        get
        {
            UrlsCollection urlsCollection =
                (UrlsCollection)base["urls"];
            return urlsCollection;
        }
    }

}

// Define the custom UrlsCollection that contains the  
// custom UrlsConfigElement elements. 
public class UrlsCollection : ConfigurationElementCollection
{
  // ...

http://msdn.microsoft.com/en-us/library/system.configuration.configurationcollectionattribute.aspx