clear Element for configSections (General Settings Schema)

  • 项目

Removes all references to inherited sections and section groups, allowing only the sections and section groups that are added by the current section and sectionGroup elements.

<clear />

Attributes and Elements

The following sections describe attributes, child elements, and parent elements.

Attributes

None.

Child Elements

None.

Parent Elements

Element Description

configuration

Specifies the required root element in every configuration file that is used by the common language runtime and the .NET Framework applications.

configSections

Specifies configuration section and namespace declarations.

sectionGroup

Defines an association between a configuration section handler and a configuration section.

Remarks

The clear element removes all references to inherited sections and section groups, allowing only the sections and section groups that are added by the current section and sectionGroup elements.

If a configuration file tries to use a configuration section after the handler reference is removed, ASP.NET issues the server error, "Unrecognized configuration section element_name."

Example

The following code example shows how to use the clear element in an application configuration file to clear sections that were previously defined in the Machine.config file.

The following code from a Machine.config file declares two sections, sampleSection and anotherSampleSection, which are read before the application configuration file.

<configuration>
   <configSections>
      <section name="sampleSection"
               type="System.Configuration.SingleTagSectionHandler" />
      <section name="anotherSampleSection"
               type="System.Configuration.NameValueSectionHandler" />
   </configSections>
   <sampleSection setting1="Value1" setting2="value two" 
                  setting3="third value" />
</configuration>

The following code from an application configuration file clears all previously declared sections. The application cannot use or retrieve settings in either of the sections that were declared in the Machine.config file. However, the application can use settings from anotherSection because anotherSection is after the clear element.

<configuration>

<configSections>

<clear/>

<section name="anotherSection"

type="System.Configuration.NameValueSectionHandler" />

</configSections>

</configuration>

Element Information

Configuration section handler

Does not apply.

Configuration member

Clear

Clear

Configurable locations

Machine.config

Root-level Web.config

Application-level Web.config

Virtual or physical directory–level Web.config

Requirements

Microsoft Internet Information Services (IIS) version 5.0, 5.1, or 6.0

The .NET Framework version 1.0, 1.1, or 2.0

Microsoft Visual Studio 2003 or Visual Studio 2005

See Also

Reference

configSections Element (General Settings Schema)
sectionGroup Element for configSections (General Settings Schema)
section Element for configSections (General Settings Schema)
remove Element for configSections (General Settings Schema)
configuration Element (General Settings Schema)

Concepts

ASP.NET Configuration File Hierarchy and Inheritance
Format of ASP.NET Configuration Files
ASP.NET Configuration Scenarios

Other Resources

General Configuration Settings (ASP.NET)
ASP.NET Configuration Settings
ASP.NET Configuration Files
Configuring ASP.NET Applications
ASP.NET Configuration API