ConfigurationElement.IsModified Method

Definition

Namespace:

System.Configuration

Assembly:

System.Configuration.ConfigurationManager.dll

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

protected:
 virtual bool IsModified();

protected virtual bool IsModified ();

abstract member IsModified : unit -> bool
override this.IsModified : unit -> bool

Protected Overridable Function IsModified () As Boolean

Returns

Boolean

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

Examples

The following example shows how to extend IsModified.

protected override bool IsModified()
{
    bool ret = base.IsModified();
    // You can enter your custom processing code here.
    return ret;
}

    Protected Overrides Function IsModified() As Boolean
        Dim ret As Boolean = MyBase.IsModified()
        ' Enter your custom processing code here.
        Return ret

    End Function 'IsModified
End Class

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

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

        UrlsCollection elements = myUrlsSection.Urls;

        IEnumerator elemEnum =
            elements.GetEnumerator();

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

        if (!myUrlsSection.ElementInformation.IsLocked)
        {

            config.Save(ConfigurationSaveMode.Full);

            // This to obsolete the MyUrls cached 
            // section and read the updated version
            // from the configuration file.
            ConfigurationManager.RefreshSection("MyUrls");
        }
        else
            Console.WriteLine(
                "Section was locked, could not update.");
    }

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

' 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. 
Shared Sub ModifyElement()
    Try
        ' Get the current configuration file.
        Dim config _
        As System.Configuration.Configuration = _
        ConfigurationManager.OpenExeConfiguration( _
        ConfigurationUserLevel.None)

        ' Get the MyUrls section.
        Dim myUrlsSection As UrlsSection = _
        config.GetSection("MyUrls")


        Dim elements As UrlsCollection = _
        myUrlsSection.Urls


        Dim elemEnum As IEnumerator = _
        elements.GetEnumerator()

        Dim i As Integer = 0
        While elemEnum.MoveNext()
            If elements(i).Name = "Microsoft" Then
                elements(i).Port = 1010
                Dim [readOnly] As Boolean = _
                elements(i).IsReadOnly()
                Exit While
            End If
            i += 1
        End While

        If Not myUrlsSection.ElementInformation.IsLocked Then

            config.Save(ConfigurationSaveMode.Full)

            ' This to obsolete the MyUrls cached 
            ' section and read the updated version 
            ' from the configuration file.
            ConfigurationManager.RefreshSection("MyUrls")
        Else
            Console.WriteLine("Section was locked, could not update.")
        End If

    Catch err As ConfigurationErrorsException
        Console.WriteLine("[ModifyElement: {0}]", _
        err.ToString())
    End Try

End Sub

Remarks

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.