SUMMARY
This step-by-step article describes how to create the
Web.config file for an ASP.NET application. The .NET Framework, and ASP.NET in
particular, uses XML-formatted .config files to configure applications. This
practice is a departure from conventional registry and metabase configuration
mechanisms. There is currently no Microsoft Management Console (MMC) snap-in or
other Microsoft-provided administration tool that you can use to create and to
modify .config files.
This article describes how to create the
Web.config file that is used to control the behavior of individual ASP.NET
applications.
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topHierarchy of .config Files
The .NET Framework relies on .config files to define configuration
options. The .config files are text-based XML files. Multiple .config files
can, and typically do, exist on a single system.
System-wide
configuration settings for the .NET Framework are defined in the Machine.config
file. The Machine.config file is located in the
%SystemRoot%\Microsoft.NET\Framework\%VersionNumber%\CONFIG\ folder. The
default settings that are contained in the Machine.config file can be modified
to affect the behavior of .NET applications on the whole system.
You
can change the ASP.NET configuration settings for a single application if you
create a Web.config file in the root folder of the application. When you do
this, the settings in the Web.config file override the settings in the
Machine.config file.
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topCreate a Web.config File
You can create a Web.config file by using a text editor such as
Notepad. You must create a text file that is named
Web.config in the root directory of your ASP.NET
application. The Web.config file must be a well-formed XML document and must
have a format similar to the
%SystemRoot%\Microsoft.NET\Framework\%VersionNumber%\CONFIG\Machine.config
file.
The Web.config file must contain only entries for configuration
items that override the settings in the Machine.config file. At a minimum, the
Web.config file must have the
<configuration> element and the
<system.web> element. These elements will contain individual configuration
elements.
The following example shows a minimal Web.config file:
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<system.web>
</system.web>
</configuration>
The first line of the Web.config file describes the document as
XML-formatted and specifies the character encoding type. This first line must
be the same for all .config files.
The lines that follow mark the
beginning and the end of the
<configuration> element and the
<system.web> element of the Web.config file. By themselves, these lines do
nothing. However, the lines provide a structure that permits you to add future
configuration settings. You add the majority of the ASP.NET configuration
settings between the <system.web> and </system.web> lines. These
lines mark the beginning and the end of the ASP.NET configuration
settings.
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