ConfigurationElement.IsModified ConfigurationElement.IsModified ConfigurationElement.IsModified ConfigurationElement.IsModified Method

定义

指示此配置元素自上次被保存或加载后,直到在派生类中被实现时,是否已经更改。Indicates whether this configuration element has been modified since it was last saved or loaded, when implemented in a derived class.

protected public:
 virtual bool IsModified();
protected internal virtual bool IsModified ();
abstract member IsModified : unit -> bool
override this.IsModified : unit -> bool
Protected Friend Overridable Function IsModified () As Boolean

返回

如果元素已修改,则为 true;否则为 falsetrue if the element has been modified; otherwise, false.

示例

下面的示例演示如何扩展IsModifiedThe 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 'UrlConfigElement 

在前面的示例所示的方法被调用时修改的配置元素,如以下示例所示。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 'ModifyElement

注解

IsModified方法确定是否这ConfigurationElement对象将写入到配置文件时Save调用方法。The IsModified method determines whether this ConfigurationElement object will be written to the configuration file when the Save method is called. 如果返回的值为 false,则表明配置文件表示该元素的当前状态。If the return value is false, it is assumed that the configuration file represents the current state of the element.

默认情况下IsModified将返回true通过索引器设置到此属性后ConfigurationElement对象。By default, IsModified returns true after a property is set through the indexer to this ConfigurationElement object.

重写IsModified方法以提供自定义此状态指示ConfigurationElement元素。Override the IsModified method to provide custom indication of the state of this ConfigurationElement element.

适用于