Implement custom section with a Configuration Element Collection c#

Question

I would like to implement a custom configuration section in a project. But something I don't understand so dont work.

I have App.config that looks like this:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <configSections>
    <section name="DepartmentConfigurationSection" type="Statistics.Config.DepartmentSection , Program1"/>
  </configSections>
  <s>
    <Cash>
      <add Number="1" Name="Money" />
    </Cash>
    <Departments>
      <add Id="1" Name="x" />
      <add Id="2" Name="y" />
    </Departments>
  </s>
</configuration>

I create a file called DepartmentSection.cs that cointains the ConfigurationElement,ConfigurationElementCollection and the ConfigurationSection. The class is like this:

 public class DepartmentConfig : ConfigurationElement
    {
        public DepartmentConfig() { }

        public DepartmentConfig(int id, string name)
        {
            Id = id;
            Name = name;
        }

        [ConfigurationProperty("Id", IsRequired = true, IsKey = true)]
        public int Id
        {
            get { return (int)this["Id"]; }
            set { this["Id"] = value; }
        }

        [ConfigurationProperty("Name",  IsRequired = true, IsKey = false)]
        public string Name
        {
            get { return (string)this["Name"]; }
            set { this["Name"] = value; }
        }
    }


    public class DepartmentCollection : ConfigurationElementCollection
    {
        public DepartmentCollection()
        {
            Console.WriteLine("ServiceCollection Constructor");
        }

        public DepartmentConfig this[int index]
        {
            get { return (DepartmentConfig)BaseGet(index); }
            set
            {
                if (BaseGet(index) != null)
                {
                    BaseRemoveAt(index);
                }
                BaseAdd(index, value);
            }
        }

        public void Add(DepartmentConfig depConfig)
        {
            BaseAdd(depConfig);
        }

        public void Clear()
        {
            BaseClear();
        }

        protected override ConfigurationElement CreateNewElement()
        {
            return new DepartmentConfig();
        }

        protected override object GetElementKey(ConfigurationElement element)
        {
            return ((DepartmentConfig)element).Id;
        }

        public void Remove(DepartmentConfig depConfig)
        {
            BaseRemove(depConfig.Id);
        }

        public void RemoveAt(int index)
        {
            BaseRemoveAt(index);
        }

        public void Remove(string name)
        {
            BaseRemove(name);
        }
    }


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

I tried to get the collection from the handler but without success. I tried like this but give me this error: "Unable to initialize the system configuration".

    DepartmentConfigurationSection serviceConfigSection =
    ConfigurationManager.GetSection("s") as DepartmentConfigurationSection;

    DepartmentConfig serviceConfig = serviceConfigSection.Departments[0];

Answer 1

The problems appear to be in your app.config (or web.config). The element that contains your custom configuration XML must match the name you have specified in the name attribute in configSections\section. For example, for your code to work as written, the app.config should look something like this:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <configSections>
    <section name="s" type="Statistics.Config.DepartmentConfigurationSection, Program1"/>
  </configSections>
  <s>
    <Cash>
      <add Number="1" Name="Money" />
    </Cash>
    <Departments>
      <add Id="1" Name="x" />
      <add Id="2" Name="y" />
    </Departments>
  </s>
</configuration>

As you can see, the section name="s" matches the name of the s element. Also, you had the type listed as Statistics.Config.DeptartmentSection, but your class name is DepartmentConfigurationSection, so it should match the class you are trying to load.