Web Configuration File

What is web.config?

Web.config is an application configuration file of The OfficialMicrosoft ASP.NET Site written in XML. It stays is the root directory of application and is responsible for controlling the application’s behaviour.

It configures Application security, SQL Database connection, session types and duration, the modules in the HTTP pipeline, HTTP handlers, WCF services inter-operability and many customization in the application context.

Other configurations like default document, directory access, default theme and validation types can also be configured.

A configuration file (web.config) is used to manage various settings that define a website. The settings are stored in XML files that are separate from your application code. In this way you can configure settings independently from your code.

Generally a website contains a single Web.config file stored inside the application root directory. However there can be many configuration files that manage settings at various levels within an application.

Uses of configuration file

ASP.NET Configuration system is used to describe the properties and behaviors of various aspects of ASP.NET applications. Configuration files help you to manage the many settings related to our website. Each file is an XML file (with the extension .config) that contains a set of configuration elements. Configuration information is stored in XML-based text files.

Advantages of XML-based Configuration files

Ø  ASP.NET Configuration system is extensible and application specific information can be stored and retrieved easily. It is human readable.

Ø  You need not restart the web server when the settings are changed in configuration file. ASP.NET automatically detects the changes and applies them to the running ASP.NET application.

Ø  You can use any standard text editor or XML parser to create and edit ASP.NET configuration files.

 Content of Web.Config file

There are number of important settings that can be stored in the configuration file. Some of the most frequently used configurations, stored conveniently inside Web.config file are:

ü Database connections

ü Application Settings

ü Configuration

ü Authentication and Authorization

Database Connections

This section of the configuration contains the connection string to our database it is within configuration element and has an element tag as <connectionstring></connectionstring> as shown below

<connectionStrings>

    <add name="DefaultConnection" connectionString="Data Source=DESKTOP-EIRHPII;Initial Catalog=csharpnaija_employees;Integrated Security=True" providerName="System.Data.SqlClient" />

   

    <add name="csharpnaija_employeesEntities" connectionString="metadata=res://*/Models.Csharpnaija.csdl|res://*/Models.Csharpnaija.ssdl|res://*/Models.Csharpnaija.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=DESKTOP-EIRHPII;initial catalog=csharpnaija_employees;integrated security=True;MultipleActiveResultSets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />

  </connectionStrings>

 AppSettings

AppSettings section contains the application setting information which is inform of key value pairs enclosed in an appsettings element as shown in code snippet below.

<appSettings>

    <add key="webpages:Version" value="3.0.0.0" />

    <add key="webpages:Enabled" value="false" />

    <add key="ClientValidationEnabled" value="true" />

    <add key="UnobtrusiveJavaScriptEnabled" value="true" />

</appSettings>

ConfigSections

This section helps you to create your own custom configuration section that can be used with the web.config file. ConfigSections should be declared just below the configuration (parent element) otherwise it is going throw you an error.

<configSections>

    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->

    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />

</configSections>

Authentication and Authorization

This section is used for setting up authentication and authorization modes, they are basically declare within system.web xml element in the configuration file as shown below

<system.web>

    <authentication mode="None" />

    <authorization>

      <allow roles="Admin"/>

      <deny users="*"/>

    </authorization>

    <compilation debug="true" targetFramework="4.7.2" />

    <httpRuntime targetFramework="4.7.2" />

</system.web>

How to Access Web.config file programmatically

We can use the C# classes to read and write the values to the Web.config file.

ConfigurationManager class is a static class with some static methods such as ConnectionStrings, AppSettings, GetSection, RefreshSection, OpenExeConfiguration etc the class is namespace System.Configuration

Example 1

To get our connection string from configuration file, we use the below code snippet

var connString = ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString;

Example 2

To get AppSettings key value from configuration file, we use the code snippet below;

var key = ConfigurationManager.AppSettings["AppKey"];