ConfigurationElementCollection ConfigurationElementCollection ConfigurationElementCollection ConfigurationElementCollection Class

Definition

Represents a configuration element containing a collection of child elements.

public ref class ConfigurationElementCollection abstract : System::Configuration::ConfigurationElement, System::Collections::ICollection
public abstract class ConfigurationElementCollection : System.Configuration.ConfigurationElement, System.Collections.ICollection
type ConfigurationElementCollection = class
    inherit ConfigurationElement
    interface ICollection
    interface IEnumerable
Public MustInherit Class ConfigurationElementCollection
Inherits ConfigurationElement
Implements ICollection
Inheritance
ConfigurationElementCollectionConfigurationElementCollectionConfigurationElementCollectionConfigurationElementCollection
Derived
Implements

Examples

The following example shows how to use the ConfigurationElementCollection.

The first example consists of three classes: UrlsSection, UrlsCollection and UrlConfigElement.The UrlsSection class uses the ConfigurationCollectionAttribute to define a custom configuration section. This section contains a URL collection (defined by the UrlsCollection class) of URL elements (defined by the UrlConfigElement class).

using System;
using System.Configuration;

// Define a UrlsSection custom section that contains a 
// UrlsCollection collection of UrlConfigElement elements.
public class UrlsSection : ConfigurationSection
{

    // Declare the UrlsCollection collection property.
    [ConfigurationProperty("urls", IsDefaultCollection = false)]
    [ConfigurationCollection(typeof(UrlsCollection),
        AddItemName = "add",
        ClearItemsName = "clear",
        RemoveItemName = "remove")]
    public UrlsCollection Urls
    {
        get
        {
            UrlsCollection urlsCollection =
                (UrlsCollection)base["urls"];

            return urlsCollection;
        }

        set
        {
            UrlsCollection urlsCollection = value;
        }
    
    }

    // Create a new instance of the UrlsSection.
    // This constructor creates a configuration element 
    // using the UrlConfigElement default values.
    // It assigns this element to the collection.
    public UrlsSection()
    {
        UrlConfigElement url = new UrlConfigElement();
        Urls.Add(url);

    }

}

// Define the UrlsCollection that contains the 
// UrlsConfigElement elements.
// This class shows how to use the ConfigurationElementCollection.
public class UrlsCollection : ConfigurationElementCollection
{
    
    
    public UrlsCollection()
    {
       
    }

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

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

    protected override Object GetElementKey(ConfigurationElement element)
    {
        return ((UrlConfigElement)element).Name;
    }

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

    new public UrlConfigElement this[string Name]
    {
        get
        {
            return (UrlConfigElement)BaseGet(Name);
        }
    }
    
    
    public int IndexOf(UrlConfigElement url)
    {
        return BaseIndexOf(url);
    }

    public void Add(UrlConfigElement url)
    {
        BaseAdd(url);

        // Your custom code goes here.
       
    }

    protected override void BaseAdd(ConfigurationElement element)
    {
        BaseAdd(element, false);

        // Your custom code goes here.
      
    }
    
    public void Remove(UrlConfigElement url)
    {
        if (BaseIndexOf(url) >= 0)
        {
            BaseRemove(url.Name);
            // Your custom code goes here.
            Console.WriteLine("UrlsCollection: {0}", "Removed collection element!");
        }
    }
    
    public void RemoveAt(int index)
    {
        BaseRemoveAt(index);

        // Your custom code goes here.
      
    }
    
    public void Remove(string name)
    {
        BaseRemove(name);

        // Your custom code goes here.
      
    }
    
    public void Clear()
    {
        BaseClear();

        // Your custom code goes here.
        Console.WriteLine("UrlsCollection: {0}", "Removed entire collection!");
    }

}

// Define the UrlsConfigElement elements that are contained 
// by the UrlsCollection.
public class UrlConfigElement : ConfigurationElement
{
    public UrlConfigElement(String name, String url, int port)
    {
        this.Name = name;
        this.Url = url;
        this.Port = port;
    }

    public UrlConfigElement()
    {

    }

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

    [ConfigurationProperty("url", DefaultValue = "http://www.contoso.com",
        IsRequired = true)]
    [RegexStringValidator(@"\w+:\/\/[\w.]+\S*")]
    public string Url
    {
        get
        {
            return (string)this["url"];
        }
        set
        {
            this["url"] = value;
        }
    }
    
    [ConfigurationProperty("port", DefaultValue = (int)4040, IsRequired = false)]
    [IntegerValidator(MinValue = 0, MaxValue = 8080, ExcludeRange = false)]
    public int Port
    {
        get
        {
            return (int)this["port"];
        }
        set
        {
            this["port"] = value;
        }
    }
    
}
Imports Microsoft.VisualBasic
Imports System
Imports System.Configuration

' Define a UrlsSection custom section that contains a 
' UrlsCollection collection of UrlConfigElement elements.
Public Class UrlsSection
    Inherits ConfigurationSection

    ' Declare the UrlsCollection collection property.
    <ConfigurationProperty("urls", IsDefaultCollection:=False), ConfigurationCollection(GetType(UrlsCollection), AddItemName:="add", ClearItemsName:="clear", RemoveItemName:="remove")>
    Public Property Urls() As UrlsCollection
        Get
            Dim urlsCollection As UrlsCollection = CType(MyBase.Item("urls"), UrlsCollection)

            Return urlsCollection
        End Get

        Set(ByVal value As UrlsCollection)
            Dim urlsCollection As UrlsCollection = value
        End Set

    End Property

    ' Create a new instance of the UrlsSection.
    ' This constructor creates a configuration element 
    ' using the UrlConfigElement default values.
    ' It assigns this element to the collection.
    Public Sub New()
        Dim url As New UrlConfigElement()
        Urls.Add(url)

    End Sub

End Class

' Define the UrlsCollection that contains the 
' UrlsConfigElement elements.
' This class shows how to use the ConfigurationElementCollection.
Public Class UrlsCollection
    Inherits System.Configuration.ConfigurationElementCollection


    Public Sub New()

    End Sub

    Public ReadOnly Property CollectionType() As ConfigurationElementCollectionType
        Get
            Return ConfigurationElementCollectionType.AddRemoveClearMap
        End Get
    End Property

    Protected Overloads Overrides Function CreateNewElement() As ConfigurationElement
        Return New UrlConfigElement()
    End Function

    Protected Overrides Function GetElementKey(ByVal element As ConfigurationElement) As Object
        Return (CType(element, UrlConfigElement)).Name
    End Function

    Default Public Shadows Property Item(ByVal index As Integer) As UrlConfigElement
        Get
            Return CType(BaseGet(index), UrlConfigElement)
        End Get
        Set(ByVal value As UrlConfigElement)
            If BaseGet(index) IsNot Nothing Then
                BaseRemoveAt(index)
            End If
            BaseAdd(value)
        End Set
    End Property

    Default Public Shadows ReadOnly Property Item(ByVal Name As String) As UrlConfigElement
        Get
            Return CType(BaseGet(Name), UrlConfigElement)
        End Get
    End Property

    Public Function IndexOf(ByVal url As UrlConfigElement) As Integer
        Return BaseIndexOf(url)
    End Function

    Public Sub Add(ByVal url As UrlConfigElement)
        BaseAdd(url)

        ' Your custom code goes here.

    End Sub

    Protected Overloads Sub BaseAdd(ByVal element As ConfigurationElement)
        BaseAdd(element, False)

        ' Your custom code goes here.

    End Sub

    Public Sub Remove(ByVal url As UrlConfigElement)
        If BaseIndexOf(url) >= 0 Then
            BaseRemove(url.Name)
            ' Your custom code goes here.
            Console.WriteLine("UrlsCollection: {0}", "Removed collection element!")
        End If
    End Sub

    Public Sub RemoveAt(ByVal index As Integer)
        BaseRemoveAt(index)

        ' Your custom code goes here.

    End Sub

    Public Sub Remove(ByVal name As String)
        BaseRemove(name)

        ' Your custom code goes here.

    End Sub

    Public Sub Clear()
        BaseClear()

        ' Your custom code goes here.
        Console.WriteLine("UrlsCollection: {0}", "Removed entire collection!")
    End Sub

End Class

' Define the UrlsConfigElement elements that are contained 
' by the UrlsCollection.
Public Class UrlConfigElement
    Inherits ConfigurationElement
    Public Sub New(ByVal name As String, ByVal url As String, ByVal port As Integer)
        Me.Name = name
        Me.Url = url
        Me.Port = port
    End Sub

    Public Sub New()

    End Sub

    <ConfigurationProperty("name", DefaultValue:="Contoso", IsRequired:=True, IsKey:=True)>
    Public Property Name() As String
        Get
            Return CStr(Me("name"))
        End Get
        Set(ByVal value As String)
            Me("name") = value
        End Set
    End Property

    <ConfigurationProperty("url", DefaultValue:="http://www.contoso.com", IsRequired:=True), RegexStringValidator("\w+:\/\/[\w.]+\S*")>
    Public Property Url() As String
        Get
            Return CStr(Me("url"))
        End Get
        Set(ByVal value As String)
            Me("url") = value
        End Set
    End Property

    <ConfigurationProperty("port", DefaultValue:=CInt(4040), IsRequired:=False), IntegerValidator(MinValue:=0, MaxValue:=8080, ExcludeRange:=False)>
    Public Property Port() As Integer
        Get
            Return CInt(Fix(Me("port")))
        End Get
        Set(ByVal value As Integer)
            Me("port") = value
        End Set
    End Property

End Class

This second code example uses the classes specified before. You combine these two examples in a console application project.

using System;
using System.Configuration;
using System.Text;

class UsingConfigurationCollectionElement
{

    // Create a custom section and save it in the 
    // application configuration file.
    static void CreateCustomSection()
    {
        try
        {

            // Get the current configuration file.
            System.Configuration.Configuration config =
                    ConfigurationManager.OpenExeConfiguration(
                    ConfigurationUserLevel.None);

            // Add the custom section to the application
            // configuration file.
            UrlsSection myUrlsSection = (UrlsSection)config.Sections["MyUrls"];

            if (myUrlsSection == null)
            {
                //  The configuration file does not contain the
                // custom section yet. Create it.
                myUrlsSection = new UrlsSection();

                config.Sections.Add("MyUrls", myUrlsSection);

                // Save the application configuration file.
                myUrlsSection.SectionInformation.ForceSave = true;
                config.Save(ConfigurationSaveMode.Modified); 
            }
            else
                if (myUrlsSection.Urls.Count == 0)
                {

                    // The configuration file contains the
                    // custom section but its element collection is empty.
                    // Initialize the collection. 
                    UrlConfigElement url = new UrlConfigElement();
                    myUrlsSection.Urls.Add(url);

                    // Save the application configuration file.
                    myUrlsSection.SectionInformation.ForceSave = true;
                    config.Save(ConfigurationSaveMode.Modified);
                }

       
            Console.WriteLine("Created custom section in the application configuration file: {0}",
                config.FilePath);
            Console.WriteLine();

        }
        catch (ConfigurationErrorsException err)
        {
            Console.WriteLine("CreateCustomSection: {0}", err.ToString());
        }

    }

    static void ReadCustomSection()
    {
        try
        {
            // Get the application configuration file.
            System.Configuration.Configuration config =
                    ConfigurationManager.OpenExeConfiguration(
                    ConfigurationUserLevel.None) as Configuration;

            // Read and display the custom section.
            UrlsSection myUrlsSection =
               config.GetSection("MyUrls") as UrlsSection;

            if (myUrlsSection == null)
                Console.WriteLine("Failed to load UrlsSection.");
            else
            {
                Console.WriteLine("Collection elements contained in the custom section collection:");
                for (int i = 0; i < myUrlsSection.Urls.Count; i++)
                {
                    Console.WriteLine("   Name={0} URL={1} Port={2}",
                        myUrlsSection.Urls[i].Name,
                        myUrlsSection.Urls[i].Url,
                        myUrlsSection.Urls[i].Port);
                }
            }

        }
        catch (ConfigurationErrorsException err)
        {
            Console.WriteLine("ReadCustomSection(string): {0}", err.ToString());
        }

    }

    // Add an element to the custom section collection.
    // This function uses the ConfigurationCollectionElement Add method.
    static void AddCollectionElement()
    {
        try
        {

            // Get the current configuration file.
            System.Configuration.Configuration config =
                    ConfigurationManager.OpenExeConfiguration(
                    ConfigurationUserLevel.None);


            // Get the custom configuration section.
            UrlsSection myUrlsSection = config.GetSection("MyUrls") as UrlsSection;


            // Add the element to the collection in the custom section.
            if (config.Sections["MyUrls"] != null)
            {
                UrlConfigElement urlElement = new UrlConfigElement();
                urlElement.Name = "Microsoft";
                urlElement.Url = "http://www.microsoft.com";
                urlElement.Port = 8080;
                
                // Use the ConfigurationCollectionElement Add method
                // to add the new element to the collection.
                myUrlsSection.Urls.Add(urlElement);
                
                
                // Save the application configuration file.
                myUrlsSection.SectionInformation.ForceSave = true;
                config.Save(ConfigurationSaveMode.Modified);
                

                Console.WriteLine("Added collection element to the custom section in the configuration file: {0}",
                    config.FilePath);
                Console.WriteLine();
            }
            else
                Console.WriteLine("You must create the custom section first.");

        }
        catch (ConfigurationErrorsException err)
        {
            Console.WriteLine("AddCollectionElement: {0}", err.ToString());
        }

    }

    // Remove element from the custom section collection.
    // This function uses one of the ConfigurationCollectionElement 
    // overloaded Remove methods.
    static void RemoveCollectionElement()
    {
        try
        {

            // Get the current configuration file.
            System.Configuration.Configuration config =
                    ConfigurationManager.OpenExeConfiguration(
                    ConfigurationUserLevel.None);


            // Get the custom configuration section.
            UrlsSection myUrlsSection = config.GetSection("MyUrls") as UrlsSection;


            // Remove the element from the custom section.
            if (config.Sections["MyUrls"] != null)
            {
                UrlConfigElement urlElement = new UrlConfigElement();
                urlElement.Name = "Microsoft";
                urlElement.Url = "http://www.microsoft.com";
                urlElement.Port = 8080;

                // Use one of the ConfigurationCollectionElement Remove 
                // overloaded methods to remove the element from the collection.
                myUrlsSection.Urls.Remove(urlElement);


                // Save the application configuration file.
                myUrlsSection.SectionInformation.ForceSave = true;
                config.Save(ConfigurationSaveMode.Full);


                Console.WriteLine("Removed collection element from he custom section in the configuration file: {0}",
                    config.FilePath);
                Console.WriteLine();
            }
            else
                Console.WriteLine("You must create the custom section first.");

        }
        catch (ConfigurationErrorsException err)
        {
            Console.WriteLine("RemoveCollectionElement: {0}", err.ToString());
        }

    }

    // Remove the collection of elements from the custom section.
    // This function uses the ConfigurationCollectionElement Clear method.
    static void ClearCollectionElements()
    {
        try
        {

            // Get the current configuration file.
            System.Configuration.Configuration config =
                    ConfigurationManager.OpenExeConfiguration(
                    ConfigurationUserLevel.None);


            // Get the custom configuration section.
            UrlsSection myUrlsSection = config.GetSection("MyUrls") as UrlsSection;


            // Remove the collection of elements from the section.
            if (config.Sections["MyUrls"] != null)
            {
                myUrlsSection.Urls.Clear();


                // Save the application configuration file.
                myUrlsSection.SectionInformation.ForceSave = true;
                config.Save(ConfigurationSaveMode.Full);


                Console.WriteLine("Removed collection of elements from he custom section in the configuration file: {0}",
                    config.FilePath);
                Console.WriteLine();
            }
            else
                Console.WriteLine("You must create the custom section first.");

        }
        catch (ConfigurationErrorsException err)
        {
            Console.WriteLine("ClearCollectionElements: {0}", err.ToString());
        }

    }

    public static void UserMenu()
    {
        string applicationName =
           Environment.GetCommandLineArgs()[0] + ".exe";
        StringBuilder buffer = new StringBuilder();

        buffer.AppendLine("Application: " + applicationName);
        buffer.AppendLine("Make your selection.");
        buffer.AppendLine("?    -- Display help.");
        buffer.AppendLine("Q,q  -- Exit the application.");
        buffer.Append("1    -- Create a custom section that");
        buffer.AppendLine(" contains a collection of elements.");
        buffer.Append("2    -- Read the custom section that");
        buffer.AppendLine(" contains a collection of custom elements.");
        buffer.Append("3    -- Add a collection element to");
        buffer.AppendLine(" the custom section.");
        buffer.Append("4    -- Remove a collection element from");
        buffer.AppendLine(" the custom section.");
        buffer.Append("5    -- Clear the collection of elements from");
        buffer.AppendLine(" the custom section.");
        
        Console.Write(buffer.ToString());
    }

    // Obtain user's input and provide
    // feedback.
    static void Main(string[] args)
    {
        // Define user selection string.
        string selection;

        // Get the name of the application.
        string appName =
          Environment.GetCommandLineArgs()[0];

        // Get user selection.
        while (true)
        {

            UserMenu();
            Console.Write("> ");
            selection = Console.ReadLine();
            if (selection != string.Empty)
                break;
        }

        while (selection.ToLower() != "q")
        {
            // Process user's input.
            switch (selection)
            {
                case "1":
                    // Create a custom section and save it in the 
                    // application configuration file.
                    CreateCustomSection();
                    break;

                case "2":
                    // Read the custom section from the
                    // application configuration file.
                    ReadCustomSection();
                    break;

                case "3":
                    // Add a collection element to the
                    // custom section.
                    AddCollectionElement();
                    break;

                case "4":
                    // Remove a collection element from the
                    // custom section.
                    RemoveCollectionElement();
                    break;

                case "5":
                    // Clear the collection of elements from the
                    // custom section.
                    ClearCollectionElements();
                    break;

                default:
                    UserMenu();
                    break;
            }
            Console.Write("> ");
            selection = Console.ReadLine();
        }
    }
}
Imports System.Configuration
Imports System.Text

Friend Class UsingConfigurationCollectionElement

    ' Create a custom section and save it in the 
    ' application configuration file.
    Private Shared Sub CreateCustomSection()
        Try

            ' Get the current configuration file.
            Dim config As System.Configuration.Configuration = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None)

            ' Add the custom section to the application
            ' configuration file.
            Dim myUrlsSection As UrlsSection = CType(config.Sections("MyUrls"), UrlsSection)

            If myUrlsSection Is Nothing Then
                '  The configuration file does not contain the
                ' custom section yet. Create it.
                myUrlsSection = New UrlsSection()

                config.Sections.Add("MyUrls", myUrlsSection)

                ' Save the application configuration file.
                myUrlsSection.SectionInformation.ForceSave = True
                config.Save(ConfigurationSaveMode.Modified)
            Else
                If myUrlsSection.Urls.Count = 0 Then

                    ' The configuration file contains the
                    ' custom section but its element collection is empty.
                    ' Initialize the collection. 
                    Dim url As New UrlConfigElement()
                    myUrlsSection.Urls.Add(url)

                    ' Save the application configuration file.
                    myUrlsSection.SectionInformation.ForceSave = True
                    config.Save(ConfigurationSaveMode.Modified)
                End If
            End If


            Console.WriteLine("Created custom section in the application configuration file: {0}", config.FilePath)
            Console.WriteLine()

        Catch err As ConfigurationErrorsException
            Console.WriteLine("CreateCustomSection: {0}", err.ToString())
        End Try

    End Sub

    Private Shared Sub ReadCustomSection()
        Try
            ' Get the application configuration file.
            Dim config As System.Configuration.Configuration = TryCast(ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None), Configuration)

            ' Read and display the custom section.
            Dim myUrlsSection As UrlsSection = TryCast(config.GetSection("MyUrls"), UrlsSection)

            If myUrlsSection Is Nothing Then
                Console.WriteLine("Failed to load UrlsSection.")
            Else
                Console.WriteLine("Collection elements contained in the custom section collection:")
                For i As Integer = 0 To myUrlsSection.Urls.Count - 1
                    Console.WriteLine("   Name={0} URL={1} Port={2}", myUrlsSection.Urls(i).Name, myUrlsSection.Urls(i).Url, myUrlsSection.Urls(i).Port)
                Next i
            End If

        Catch err As ConfigurationErrorsException
            Console.WriteLine("ReadCustomSection(string): {0}", err.ToString())
        End Try

    End Sub

    ' Add an element to the custom section collection.
    ' This function uses the ConfigurationCollectionElement Add method.
    Private Shared Sub AddCollectionElement()
        Try

            ' Get the current configuration file.
            Dim config As System.Configuration.Configuration = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None)


            ' Get the custom configuration section.
            Dim myUrlsSection As UrlsSection = TryCast(config.GetSection("MyUrls"), UrlsSection)


            ' Add the element to the collection in the custom section.
            If config.Sections("MyUrls") IsNot Nothing Then
                Dim urlElement As New UrlConfigElement()
                urlElement.Name = "Microsoft"
                urlElement.Url = "http://www.microsoft.com"
                urlElement.Port = 8080

                ' Use the ConfigurationCollectionElement Add method
                ' to add the new element to the collection.
                myUrlsSection.Urls.Add(urlElement)


                ' Save the application configuration file.
                myUrlsSection.SectionInformation.ForceSave = True
                config.Save(ConfigurationSaveMode.Modified)


                Console.WriteLine("Added collection element to the custom section in the configuration file: {0}", config.FilePath)
                Console.WriteLine()
            Else
                Console.WriteLine("You must create the custom section first.")
            End If

        Catch err As ConfigurationErrorsException
            Console.WriteLine("AddCollectionElement: {0}", err.ToString())
        End Try

    End Sub

    ' Remove element from the custom section collection.
    ' This function uses one of the ConfigurationCollectionElement 
    ' overloaded Remove methods.
    Private Shared Sub RemoveCollectionElement()
        Try

            ' Get the current configuration file.
            Dim config As System.Configuration.Configuration = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None)


            ' Get the custom configuration section.
            Dim myUrlsSection As UrlsSection = TryCast(config.GetSection("MyUrls"), UrlsSection)


            ' Remove the element from the custom section.
            If config.Sections("MyUrls") IsNot Nothing Then
                Dim urlElement As New UrlConfigElement()
                urlElement.Name = "Microsoft"
                urlElement.Url = "http://www.microsoft.com"
                urlElement.Port = 8080

                ' Use one of the ConfigurationCollectionElement Remove 
                ' overloaded methods to remove the element from the collection.
                myUrlsSection.Urls.Remove(urlElement)


                ' Save the application configuration file.
                myUrlsSection.SectionInformation.ForceSave = True
                config.Save(ConfigurationSaveMode.Full)


                Console.WriteLine("Removed collection element from he custom section in the configuration file: {0}", config.FilePath)
                Console.WriteLine()
            Else
                Console.WriteLine("You must create the custom section first.")
            End If

        Catch err As ConfigurationErrorsException
            Console.WriteLine("RemoveCollectionElement: {0}", err.ToString())
        End Try

    End Sub

    ' Remove the collection of elements from the custom section.
    ' This function uses the ConfigurationCollectionElement Clear method.
    Private Shared Sub ClearCollectionElements()
        Try

            ' Get the current configuration file.
            Dim config As System.Configuration.Configuration = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None)


            ' Get the custom configuration section.
            Dim myUrlsSection As UrlsSection = TryCast(config.GetSection("MyUrls"), UrlsSection)


            ' Remove the collection of elements from the section.
            If config.Sections("MyUrls") IsNot Nothing Then
                myUrlsSection.Urls.Clear()


                ' Save the application configuration file.
                myUrlsSection.SectionInformation.ForceSave = True
                config.Save(ConfigurationSaveMode.Full)


                Console.WriteLine("Removed collection of elements from he custom section in the configuration file: {0}", config.FilePath)
                Console.WriteLine()
            Else
                Console.WriteLine("You must create the custom section first.")
            End If

        Catch err As ConfigurationErrorsException
            Console.WriteLine("ClearCollectionElements: {0}", err.ToString())
        End Try

    End Sub

    Public Shared Sub UserMenu()
        Dim applicationName As String = Environment.GetCommandLineArgs()(0) & ".exe"
        Dim buffer As New StringBuilder()

        buffer.AppendLine("Application: " & applicationName)
        buffer.AppendLine("Make your selection.")
        buffer.AppendLine("?    -- Display help.")
        buffer.AppendLine("Q,q  -- Exit the application.")
        buffer.Append("1    -- Create a custom section that")
        buffer.AppendLine(" contains a collection of elements.")
        buffer.Append("2    -- Read the custom section that")
        buffer.AppendLine(" contains a collection of custom elements.")
        buffer.Append("3    -- Add a collection element to")
        buffer.AppendLine(" the custom section.")
        buffer.Append("4    -- Remove a collection element from")
        buffer.AppendLine(" the custom section.")
        buffer.Append("5    -- Clear the collection of elements from")
        buffer.AppendLine(" the custom section.")

        Console.Write(buffer.ToString())
    End Sub

    ' Obtain user's input and provide
    ' feedback.
    Shared Sub Main(ByVal args() As String)
        ' Define user selection string.
        Dim selection As String

        ' Get the name of the application.
        Dim appName As String = Environment.GetCommandLineArgs()(0)

        ' Get user selection.
        Do

            UserMenu()
            Console.Write("> ")
            selection = Console.ReadLine()
            If selection <> String.Empty Then
                Exit Do
            End If
        Loop

        Do While selection.ToLower() <> "q"
            ' Process user's input.
            Select Case selection
                Case "1"
                    ' Create a custom section and save it in the 
                    ' application configuration file.
                    CreateCustomSection()

                Case "2"
                    ' Read the custom section from the
                    ' application configuration file.
                    ReadCustomSection()

                Case "3"
                    ' Add a collection element to the
                    ' custom section.
                    AddCollectionElement()

                Case "4"
                    ' Remove a collection element from the
                    ' custom section.
                    RemoveCollectionElement()

                Case "5"
                    ' Clear the collection of elements from the
                    ' custom section.
                    ClearCollectionElements()

                Case Else
                    UserMenu()
            End Select
            Console.Write("> ")
            selection = Console.ReadLine()
        Loop
    End Sub
End Class

When you run the console application, an instance of the UrlsSection class is created and the following configuration elements are generated in the application configuration file:

<configuration>  
    <configSections>  
        <section name="MyUrls" type="UrlsSection,   
          ConfigurationElementCollection, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" />  
    </configSections>  
    <MyUrls>  
        <urls>  
           <add name="Contoso" url="http://www.contoso.com" port="4040 />  
        </urls>  
    </MyUrls>  
</configuration  

Remarks

The ConfigurationElementCollection represents a collection of elements within a configuration file.

Note

An element within a configuration file refers to a basic XML element or a section. A simple element is an XML tag with related attributes, if any. A simple element constitutes a section. Complex sections can contain one or more simple elements, a collection of elements, and other sections.

You use the ConfigurationElementCollection to work with a collection of ConfigurationElement objects. Implement this class to add collections of custom ConfigurationElement elements to a ConfigurationSection.

Notes to Inheritors

You can use a programmatic or a declarative (attributed) coding model to create a custom configuration element.

The programmatic model requires that for each element attribute you create a property to get and set its value, and that you add it to the internal property bag of the underlying ConfigurationElement base class.

The declarative model, also referred to as the attributed model, allows you to define an element attribute by using a property and configuring it with attributes. These attributes instruct the ASP.NET configuration system about the property types and their default values. ASP.NET can use reflection to obtain this information and then create the element property objects and perform the required initialization.

Constructors

ConfigurationElementCollection() ConfigurationElementCollection() ConfigurationElementCollection() ConfigurationElementCollection()

Initializes a new instance of the ConfigurationElementCollection class.

ConfigurationElementCollection(IComparer) ConfigurationElementCollection(IComparer) ConfigurationElementCollection(IComparer) ConfigurationElementCollection(IComparer)

Creates a new instance of the ConfigurationElementCollection class.

Properties

AddElementName AddElementName AddElementName AddElementName

Gets or sets the name of the ConfigurationElement to associate with the add operation in the ConfigurationElementCollection when overridden in a derived class.

ClearElementName ClearElementName ClearElementName ClearElementName

Gets or sets the name for the ConfigurationElement to associate with the clear operation in the ConfigurationElementCollection when overridden in a derived class.

CollectionType CollectionType CollectionType CollectionType

Gets the type of the ConfigurationElementCollection.

Count Count Count Count

Gets the number of elements in the collection.

CurrentConfiguration CurrentConfiguration CurrentConfiguration CurrentConfiguration

Gets a reference to the top-level Configuration instance that represents the configuration hierarchy that the current ConfigurationElement instance belongs to.

(Inherited from ConfigurationElement)
ElementInformation ElementInformation ElementInformation ElementInformation

Gets an ElementInformation object that contains the non-customizable information and functionality of the ConfigurationElement object.

(Inherited from ConfigurationElement)
ElementName ElementName ElementName ElementName

Gets the name used to identify this collection of elements in the configuration file when overridden in a derived class.

ElementProperty ElementProperty ElementProperty ElementProperty

Gets the ConfigurationElementProperty object that represents the ConfigurationElement object itself.

(Inherited from ConfigurationElement)
EmitClear EmitClear EmitClear EmitClear

Gets or sets a value that specifies whether the collection has been cleared.

EvaluationContext EvaluationContext EvaluationContext EvaluationContext

Gets the ContextInformation object for the ConfigurationElement object.

(Inherited from ConfigurationElement)
HasContext HasContext HasContext HasContext

Gets a value that indicates whether the CurrentConfiguration property is null.

(Inherited from ConfigurationElement)
IsSynchronized IsSynchronized IsSynchronized IsSynchronized

Gets a value indicating whether access to the collection is synchronized.

Item[ConfigurationProperty] Item[ConfigurationProperty] Item[ConfigurationProperty] Item[ConfigurationProperty]

Gets or sets a property or attribute of this configuration element.

(Inherited from ConfigurationElement)
Item[String] Item[String] Item[String] Item[String]

Gets or sets a property, attribute, or child element of this configuration element.

(Inherited from ConfigurationElement)
LockAllAttributesExcept LockAllAttributesExcept LockAllAttributesExcept LockAllAttributesExcept

Gets the collection of locked attributes.

(Inherited from ConfigurationElement)
LockAllElementsExcept LockAllElementsExcept LockAllElementsExcept LockAllElementsExcept

Gets the collection of locked elements.

(Inherited from ConfigurationElement)
LockAttributes LockAttributes LockAttributes LockAttributes

Gets the collection of locked attributes

(Inherited from ConfigurationElement)
LockElements LockElements LockElements LockElements

Gets the collection of locked elements.

(Inherited from ConfigurationElement)
LockItem LockItem LockItem LockItem

Gets or sets a value indicating whether the element is locked.

(Inherited from ConfigurationElement)
Properties Properties Properties Properties

Gets the collection of properties.

(Inherited from ConfigurationElement)
RemoveElementName RemoveElementName RemoveElementName RemoveElementName

Gets or sets the name of the ConfigurationElement to associate with the remove operation in the ConfigurationElementCollection when overridden in a derived class.

SyncRoot SyncRoot SyncRoot SyncRoot

Gets an object used to synchronize access to the ConfigurationElementCollection.

ThrowOnDuplicate ThrowOnDuplicate ThrowOnDuplicate ThrowOnDuplicate

Gets a value indicating whether an attempt to add a duplicate ConfigurationElement to the ConfigurationElementCollection will cause an exception to be thrown.

Methods

BaseAdd(ConfigurationElement) BaseAdd(ConfigurationElement) BaseAdd(ConfigurationElement) BaseAdd(ConfigurationElement)

Adds a configuration element to the ConfigurationElementCollection.

BaseAdd(ConfigurationElement, Boolean) BaseAdd(ConfigurationElement, Boolean) BaseAdd(ConfigurationElement, Boolean) BaseAdd(ConfigurationElement, Boolean)

Adds a configuration element to the configuration element collection.

BaseAdd(Int32, ConfigurationElement) BaseAdd(Int32, ConfigurationElement) BaseAdd(Int32, ConfigurationElement) BaseAdd(Int32, ConfigurationElement)

Adds a configuration element to the configuration element collection.

BaseClear() BaseClear() BaseClear() BaseClear()

Removes all configuration element objects from the collection.

BaseGet(Int32) BaseGet(Int32) BaseGet(Int32) BaseGet(Int32)

Gets the configuration element at the specified index location.

BaseGet(Object) BaseGet(Object) BaseGet(Object) BaseGet(Object)

Returns the configuration element with the specified key.

BaseGetAllKeys() BaseGetAllKeys() BaseGetAllKeys() BaseGetAllKeys()

Returns an array of the keys for all of the configuration elements contained in the ConfigurationElementCollection.

BaseGetKey(Int32) BaseGetKey(Int32) BaseGetKey(Int32) BaseGetKey(Int32)

Gets the key for the ConfigurationElement at the specified index location.

BaseIndexOf(ConfigurationElement) BaseIndexOf(ConfigurationElement) BaseIndexOf(ConfigurationElement) BaseIndexOf(ConfigurationElement)

Indicates the index of the specified ConfigurationElement.

BaseIsRemoved(Object) BaseIsRemoved(Object) BaseIsRemoved(Object) BaseIsRemoved(Object)

Indicates whether the ConfigurationElement with the specified key has been removed from the ConfigurationElementCollection.

BaseRemove(Object) BaseRemove(Object) BaseRemove(Object) BaseRemove(Object)

Removes a ConfigurationElement from the collection.

BaseRemoveAt(Int32) BaseRemoveAt(Int32) BaseRemoveAt(Int32) BaseRemoveAt(Int32)

Removes the ConfigurationElement at the specified index location.

CopyTo(ConfigurationElement[], Int32) CopyTo(ConfigurationElement[], Int32) CopyTo(ConfigurationElement[], Int32) CopyTo(ConfigurationElement[], Int32)

Copies the contents of the ConfigurationElementCollection to an array.

CreateNewElement() CreateNewElement() CreateNewElement() CreateNewElement()

When overridden in a derived class, creates a new ConfigurationElement.

CreateNewElement(String) CreateNewElement(String) CreateNewElement(String) CreateNewElement(String)

Creates a new ConfigurationElement when overridden in a derived class.

DeserializeElement(XmlReader, Boolean) DeserializeElement(XmlReader, Boolean) DeserializeElement(XmlReader, Boolean) DeserializeElement(XmlReader, Boolean)

Reads XML from the configuration file.

(Inherited from ConfigurationElement)
Equals(Object) Equals(Object) Equals(Object) Equals(Object)

Compares the ConfigurationElementCollection to the specified object.

GetElementKey(ConfigurationElement) GetElementKey(ConfigurationElement) GetElementKey(ConfigurationElement) GetElementKey(ConfigurationElement)

Gets the element key for a specified configuration element when overridden in a derived class.

GetEnumerator() GetEnumerator() GetEnumerator() GetEnumerator()

Gets an IEnumerator which is used to iterate through the ConfigurationElementCollection.

GetHashCode() GetHashCode() GetHashCode() GetHashCode()

Gets a unique value representing the ConfigurationElementCollection instance.

GetTransformedAssemblyString(String) GetTransformedAssemblyString(String) GetTransformedAssemblyString(String) GetTransformedAssemblyString(String)

Returns the transformed version of the specified assembly name.

(Inherited from ConfigurationElement)
GetTransformedTypeString(String) GetTransformedTypeString(String) GetTransformedTypeString(String) GetTransformedTypeString(String)

Returns the transformed version of the specified type name.

(Inherited from ConfigurationElement)
GetType() GetType() GetType() GetType()

Gets the Type of the current instance.

(Inherited from Object)
Init() Init() Init() Init()

Sets the ConfigurationElement object to its initial state.

(Inherited from ConfigurationElement)
InitializeDefault() InitializeDefault() InitializeDefault() InitializeDefault()

Used to initialize a default set of values for the ConfigurationElement object.

(Inherited from ConfigurationElement)
IsElementName(String) IsElementName(String) IsElementName(String) IsElementName(String)

Indicates whether the specified ConfigurationElement exists in the ConfigurationElementCollection.

IsElementRemovable(ConfigurationElement) IsElementRemovable(ConfigurationElement) IsElementRemovable(ConfigurationElement) IsElementRemovable(ConfigurationElement)

Indicates whether the specified ConfigurationElement can be removed from the ConfigurationElementCollection.

IsModified() IsModified() IsModified() IsModified()

Indicates whether this ConfigurationElementCollection has been modified since it was last saved or loaded when overridden in a derived class.

IsReadOnly() IsReadOnly() IsReadOnly() IsReadOnly()

Indicates whether the ConfigurationElementCollection object is read only.

ListErrors(IList) ListErrors(IList) ListErrors(IList) ListErrors(IList)

Adds the invalid-property errors in this ConfigurationElement object, and in all subelements, to the passed list.

(Inherited from ConfigurationElement)
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
OnDeserializeUnrecognizedAttribute(String, String) OnDeserializeUnrecognizedAttribute(String, String) OnDeserializeUnrecognizedAttribute(String, String) OnDeserializeUnrecognizedAttribute(String, String)

Gets a value indicating whether an unknown attribute is encountered during deserialization.

(Inherited from ConfigurationElement)
OnDeserializeUnrecognizedElement(String, XmlReader) OnDeserializeUnrecognizedElement(String, XmlReader) OnDeserializeUnrecognizedElement(String, XmlReader) OnDeserializeUnrecognizedElement(String, XmlReader)

Causes the configuration system to throw an exception.

OnRequiredPropertyNotFound(String) OnRequiredPropertyNotFound(String) OnRequiredPropertyNotFound(String) OnRequiredPropertyNotFound(String)

Throws an exception when a required property is not found.

(Inherited from ConfigurationElement)
PostDeserialize() PostDeserialize() PostDeserialize() PostDeserialize()

Called after deserialization.

(Inherited from ConfigurationElement)
PreSerialize(XmlWriter) PreSerialize(XmlWriter) PreSerialize(XmlWriter) PreSerialize(XmlWriter)

Called before serialization.

(Inherited from ConfigurationElement)
Reset(ConfigurationElement) Reset(ConfigurationElement) Reset(ConfigurationElement) Reset(ConfigurationElement)

Resets the ConfigurationElementCollection to its unmodified state when overridden in a derived class.

ResetModified() ResetModified() ResetModified() ResetModified()

Resets the value of the IsModified() property to false when overridden in a derived class.

SerializeElement(XmlWriter, Boolean) SerializeElement(XmlWriter, Boolean) SerializeElement(XmlWriter, Boolean) SerializeElement(XmlWriter, Boolean)

Writes the configuration data to an XML element in the configuration file when overridden in a derived class.

SerializeToXmlElement(XmlWriter, String) SerializeToXmlElement(XmlWriter, String) SerializeToXmlElement(XmlWriter, String) SerializeToXmlElement(XmlWriter, String)

Writes the outer tags of this configuration element to the configuration file when implemented in a derived class.

(Inherited from ConfigurationElement)
SetPropertyValue(ConfigurationProperty, Object, Boolean) SetPropertyValue(ConfigurationProperty, Object, Boolean) SetPropertyValue(ConfigurationProperty, Object, Boolean) SetPropertyValue(ConfigurationProperty, Object, Boolean)

Sets a property to the specified value.

(Inherited from ConfigurationElement)
SetReadOnly() SetReadOnly() SetReadOnly() SetReadOnly()

Sets the IsReadOnly() property for the ConfigurationElementCollection object and for all sub-elements.

ToString() ToString() ToString() ToString()

Returns a string that represents the current object.

(Inherited from Object)
Unmerge(ConfigurationElement, ConfigurationElement, ConfigurationSaveMode) Unmerge(ConfigurationElement, ConfigurationElement, ConfigurationSaveMode) Unmerge(ConfigurationElement, ConfigurationElement, ConfigurationSaveMode) Unmerge(ConfigurationElement, ConfigurationElement, ConfigurationSaveMode)

Explicit Interface Implementations

ICollection.CopyTo(Array, Int32) ICollection.CopyTo(Array, Int32) ICollection.CopyTo(Array, Int32) ICollection.CopyTo(Array, Int32)

Copies the ConfigurationElementCollection to an array.

Extension Methods

Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable)

Casts the elements of an IEnumerable to the specified type.

OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable)

Filters the elements of an IEnumerable based on a specified type.

AsParallel(IEnumerable) AsParallel(IEnumerable) AsParallel(IEnumerable) AsParallel(IEnumerable)

Enables parallelization of a query.

AsQueryable(IEnumerable) AsQueryable(IEnumerable) AsQueryable(IEnumerable) AsQueryable(IEnumerable)

Converts an IEnumerable to an IQueryable.

Applies to

See Also