ConfigurationPropertyAttribute Class
 
System_CAPS_noteNote

The .NET API Reference documentation has a new home. Visit the .NET API Browser on docs.microsoft.com to see the new experience.

Declaratively instructs the .NET Framework to instantiate a configuration property. This class cannot be inherited.

Namespace:   System.Configuration
Assembly:  System.Configuration (in System.Configuration.dll)

SystemObject
   SystemAttribute
    System.ConfigurationConfigurationPropertyAttribute

[AttributeUsageAttribute(AttributeTargets.Property)]
public sealed class ConfigurationPropertyAttribute : Attribute
[AttributeUsageAttribute(AttributeTargets::Property)]
public ref class ConfigurationPropertyAttribute sealed : Attribute
[<Sealed>]
[<AttributeUsageAttribute(AttributeTargets.Property)>]
type ConfigurationPropertyAttribute = 
    class
        inherit Attribute
    end
<AttributeUsageAttribute(AttributeTargets.Property)>
Public NotInheritable Class ConfigurationPropertyAttribute
	Inherits Attribute
NameDescription
System_CAPS_pubmethod ConfigurationPropertyAttribute

This API supports the product infrastructure and is not intended to be used directly from your code. Initializes a new instance of ConfigurationPropertyAttribute class.

NameDescription
System_CAPS_pubproperty

Gets or sets the default value for the decorated property.

System_CAPS_pubproperty

Gets or sets a value indicating whether this is the default property collection for the decorated configuration property.

System_CAPS_pubproperty

Gets or sets a value indicating whether this is a key property for the decorated element property.

System_CAPS_pubproperty

Gets or sets a value indicating whether the decorated element property is required.

System_CAPS_pubproperty

Gets the name of the decorated configuration-element property.

System_CAPS_pubproperty

Gets or sets the ConfigurationPropertyOptions for the decorated configuration-element property.

System_CAPS_pubproperty

When implemented in a derived class, gets a unique identifier for this Attribute.(Inherited from Attribute.)

NameDescription
System_CAPS_pubmethod Equals

This API supports the product infrastructure and is not intended to be used directly from your code. Returns a value that indicates whether this instance is equal to a specified object.(Inherited from Attribute.)

System_CAPS_pubmethod GetHashCode

Returns the hash code for this instance.(Inherited from Attribute.)

System_CAPS_pubmethod GetType

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethod IsDefaultAttribute

When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class.(Inherited from Attribute.)

System_CAPS_pubmethod Match

When overridden in a derived class, returns a value that indicates whether this instance equals a specified object.(Inherited from Attribute.)

System_CAPS_pubmethod ToString

Returns a string that represents the current object.(Inherited from Object.)

NameDescription
System_CAPS_pubinterface System_CAPS_privmethod _AttributeGetIDsOfNames

Maps a set of names to a corresponding set of dispatch identifiers.(Inherited from Attribute.)

System_CAPS_pubinterface System_CAPS_privmethod _AttributeGetTypeInfo

Retrieves the type information for an object, which can be used to get the type information for an interface.(Inherited from Attribute.)

System_CAPS_pubinterface System_CAPS_privmethod _AttributeGetTypeInfoCount

Retrieves the number of type information interfaces that an object provides (either 0 or 1).(Inherited from Attribute.)

System_CAPS_pubinterface System_CAPS_privmethod _AttributeInvoke

Provides access to properties and methods exposed by an object.(Inherited from Attribute.)

You use the ConfigurationPropertyAttribute to decorate a configuration property, which will instruct the .NET Framework to instantiate and to initialize the property using the value of the decorating parameter.

System_CAPS_noteNote

The simplest way to create a custom configuration element is to use the attributed (declarative) model. You declare the custom public properties and decorate them with the ConfigurationPropertyAttribute attribute. For each property marked with this attribute, the .NET Framework uses reflection to read the decorating parameters and create a related ConfigurationProperty instance. You can also use the programmatic model, in which case it is your responsibility to declare the custom public properties and return their collection.

The .NET Framework configuration system provides attribute types that you can use during the creation of custom configuration elements. There are two kinds of attribute types:

  1. The types instructing the .NET Framework how to instantiate the custom configuration-element properties. These types include:

  2. The types instructing the .NET Framework how to validate the custom configuration-element properties. These types include:

The following example shows how to define the properties of a custom ConfigurationSection object using the ConfigurationPropertyAttribute attribute.

The example contains two classes. The UrlsSection custom class uses the ConfigurationPropertyAttribute to define its own properties. The UsingConfigurationPropertyAttribute class uses the UrlsSection to read and write the custom section in the application configuration file.

using System;
using System.Configuration;


// Define a custom section.
// This class shows how to use the ConfigurationPropertyAttribute.
public class UrlsSection : ConfigurationSection
{
    [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)0, 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 custom section.
' This class shows how to use the ConfigurationPropertyAttribute.
Public Class UrlsSection
    Inherits ConfigurationSection
    <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:=0, 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
using System;
using System.Configuration;

public class UsingConfigurationPropertyAttribute
{

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

            // Create a custom configuration section.
            UrlsSection customSection = new UrlsSection();

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

            // Add the custom section to the application
            // configuration file.
            if (config.Sections["CustomSection"] == null)
            {
                config.Sections.Add("CustomSection", customSection);
            }


            // Save the application configuration file.
            customSection.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 customSection =
                config.GetSection("CustomSection") as UrlsSection;
            Console.WriteLine("Reading custom section from the configuration file.");
            Console.WriteLine("Section name: {0}", customSection.Name);
            Console.WriteLine("Url: {0}", customSection.Url);
            Console.WriteLine("Port: {0}", customSection.Port);
            Console.WriteLine();
        }
        catch (ConfigurationErrorsException err)
        {
            Console.WriteLine("ReadCustomSection(string): {0}", err.ToString());
        }

    }

    static void Main(string[] args)
    {

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

        // Create a custom section and save it in the 
        // application configuration file.
        CreateCustomSection();

        // Read the custom section saved in the
        // application configuration file.
        ReadCustomSection();

        Console.WriteLine("Press enter to exit.");

        Console.ReadLine();
    }
}
Imports System
Imports System.Configuration

Public Class UsingConfigurationPropertyAttribute

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

            ' Create a custom configuration section.
            Dim customSection As New UrlsSection()

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

            ' Add the custom section to the application
            ' configuration file.
            If config.Sections("CustomSection") Is Nothing Then
                config.Sections.Add("CustomSection", customSection)
            End If


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

            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 customSection As UrlsSection = TryCast(config.GetSection("CustomSection"), UrlsSection)
            Console.WriteLine("Reading custom section from the configuration file.")
            Console.WriteLine("Section name: {0}", customSection.Name)
            Console.WriteLine("Url: {0}", customSection.Url)
            Console.WriteLine("Port: {0}", customSection.Port)
            Console.WriteLine()
        Catch err As ConfigurationErrorsException
            Console.WriteLine("ReadCustomSection(string): {0}", err.ToString())
        End Try

    End Sub

    Shared Sub Main(ByVal args() As String)

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

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

        ' Read the custom section saved in the
        ' application configuration file.
        ReadCustomSection()

        Console.WriteLine("Press enter to exit.")

        Console.ReadLine()
    End Sub
End Class

The following is an excerpt of the configuration file containing the custom section as defined in the previous sample.

<?xml version="1.0" encoding="utf-8"?>
<configuration>
    <configSections>
        <section name="CustomSection" type="UrlsSection, UsingConfigurationPropertyAttribute, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" />
    </configSections>
    <CustomSection name="Contoso" url="http://www.contoso.com" />
</configuration>
.NET Framework
Available since 2.0

Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Return to top