C# 从web.config读取自定义配置返回null

我试图从databases/add元素中读取值，但每次它都抛出异常。这里怎么了。。。我不明白

如果这是一个线索的话，这个代码在它自己的程序集中

web.config中的配置

<sectionGroup name="sessionFactoryConfiguration">
  <section name="Databases" type="Boot.Multitenancy.Configuration.SessionFactoryConfiguration, ConfigurationCollectionAttribute"/>
</sectionGroup>


<sessionFactoryConfiguration>
  <Databases>
        <add name="www.domain.com" autoPersist="true" dbType="SqlCe"/>
        <add name="www.domain.net" autoPersist="true" dbType="SqlCe"/>
</Databases>
</sessionFactoryConfiguration>

各节的执行情况

public class DatabaseSection : ConfigurationElement
{
    public DatabaseSection() { }
    public DatabaseSection(String name, bool autoPersist, DbType dbtype)
    {
        this.Name = name;
        this.AutoPersist = autoPersist;
        this.DbType = dbtype;
    }

    [ConfigurationProperty("name")]
    public String Name
    {
        get { return (String)this["name"]; }
        set { this["name"] = value; }
    }

    [ConfigurationProperty("autoPersist", DefaultValue = false, IsRequired = false)]
    public Boolean AutoPersist
    {
        get { return (Boolean)this["autoPersist"]; }
        set { this["autoPersist"] = value; }
    }

    /// <summary>
    /// DbType
    /// </summary>
    [ConfigurationProperty("dbType", DefaultValue = DbType.SqlCe, IsRequired = false)]
    public DbType DbType
    {
        get { return (DbType)this["dbType"]; }
        set { this["dbType"] = value; }
    }
}

---

这么简单。。。我只需要在web配置中将ConfigurationCollectionAttribute更改为我的assemblyname

在每个示例中，它们都引用此属性

发件人： 节名=sessionFactoryConfiguration类型=Boot.Multitenance.Configuration.sessionFactoryConfiguration，ConfigurationCollectionAttribute/>

致：

---

section name=sessionFactoryConfiguration type=Boot.Multitenancy.Configuration.sessionFactoryConfiguration，Boot.Multitenancy/>

它会引发什么异常？我只是打印出未加载，因为如果有一个值它应该工作。应该有一个异常详细信息。如果我添加：var db=conf.Databases；我得到：对象引用未设置为对象的实例。

public class DatabaseSection : ConfigurationElement
{
    public DatabaseSection() { }
    public DatabaseSection(String name, bool autoPersist, DbType dbtype)
    {
        this.Name = name;
        this.AutoPersist = autoPersist;
        this.DbType = dbtype;
    }

    [ConfigurationProperty("name")]
    public String Name
    {
        get { return (String)this["name"]; }
        set { this["name"] = value; }
    }

    [ConfigurationProperty("autoPersist", DefaultValue = false, IsRequired = false)]
    public Boolean AutoPersist
    {
        get { return (Boolean)this["autoPersist"]; }
        set { this["autoPersist"] = value; }
    }

    /// <summary>
    /// DbType
    /// </summary>
    [ConfigurationProperty("dbType", DefaultValue = DbType.SqlCe, IsRequired = false)]
    public DbType DbType
    {
        get { return (DbType)this["dbType"]; }
        set { this["dbType"] = value; }
    }
}

public class SessionFactoryConfiguration : ConfigurationSection
{
    [ConfigurationProperty("Databases", IsDefaultCollection = false)]
    [ConfigurationCollection(typeof(DatabaseCollection), AddItemName = "add", ClearItemsName = "clear", RemoveItemName = "remove")]
    public DatabaseCollection Databases
    {
        get { return (DatabaseCollection)base["Databases"]; }
    }
}


public class DatabaseCollection : ConfigurationElementCollection
{
    public DatabaseCollection()
    {
        Add((DatabaseSection)CreateNewElement());
    }

    public override ConfigurationElementCollectionType CollectionType
    {
        get { return ConfigurationElementCollectionType.AddRemoveClearMap; }
    }

    protected override ConfigurationElement CreateNewElement()
    {
        return new DatabaseSection();
    }
 ....//long code

}