ConfigurationElement.IsModified Method

Note: This method is new in the .NET Framework version 2.0.

Indicates whether this configuration element has been modified since it was last saved or loaded, when implemented in a derived class.

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

protected internal virtual bool IsModified ()
protected boolean IsModified ()
protected internal function IsModified () : boolean

Return Value

true if the element has been modified; otherwise, false.

The IsModified method determines whether this ConfigurationElement object will be written to the configuration file when the Save method is called. If the return value is false, it is assumed that the configuration file represents the current state of the element.

By default, IsModified returns true after a property is set through the indexer to this ConfigurationElement object.

Override the IsModified method to provide custom indication of the state of this ConfigurationElement element.

The following example shows how to extend IsModified.

protected override bool IsModified()
    bool ret = base.IsModified();

    // Enter your custom processing code here.

    Console.WriteLine("UrlConfigElement.IsModified() called.");

    return ret;

The method shown in the previous example is called when a configuration element is modified, as in the following example.

// Show how to use IsModified.
// This method modifies the port property
// of the url element named Microsoft and
// saves the modification to the configuration
// file. This in turn will cause the overriden
// UrlConfigElement.IsModified() mathod to be called. 
static void ModifyElement()
        // Get the configuration file.
        System.Configuration.Configuration config =

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

        UrlsCollection elements = myUrlsSection.Urls;

        IEnumerator elemEnum =

        int i = 0;
        while (elemEnum.MoveNext())
            if (elements[i].Name == "Microsoft")
                elements[i].Port = 1010;
                bool readOnly = elements[i].IsReadOnly();
            i += 1;

        if (!myUrlsSection.ElementInformation.IsLocked)


            // This to obsolete the MyUrls cached 
            // section and read the updated version
            // from the configuration file.
                "Section was locked, could not update.");

    catch (ConfigurationErrorsException err)
        Console.WriteLine("[ModifyElement: {0]",

Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0

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