如何从多个位置标签中有多个appSettings标签的配置文件中读取appSettings？

Question

I am suppose to retrieve the appSettings key to read in a text file. now the problem is in my web.config file , there are multiple location tags and inside them we have multiple appSettings tag.Hence my code is failing to target the location tag appSettings which i actually need.

  <location path="BidOnline">
    <appSettings/>
    <system.web>
      <authorization>
        <allow users="*"/>
        <!-- Allow all users to the public location -->
      </authorization>
    </system.web>
  </location>
  <location path="Profdev/Public">
    <appSettings/>
    <system.web>
      <authorization>
        <allow users="*"/>
        <!-- Allow all users to the public location -->
      </authorization>
    </system.web>
  </location>

  <location path="Punchout">
    <system.webServer>
      <httpProtocol>
        <customHeaders>
          <clear />
          <add name="X-XSS-Protection" value="0"/>
        </customHeaders> 
      </httpProtocol>
    </system.webServer>
  </location>
  <!-- FACTS Service -->
  <location path="Services/Facts">
    <appSettings>
      <!-- Disabeling the security should ONLY be done in test mode. -->
      <add key="DisableSecurity" value="false"/>
      <!-- 
        The ip addresses listed below are the only address that can
        be used while security is enabled (by default.)  Any other
        ip address attempting to post to the service will not be 
        able to.
      -->
      <add key="IPAddresses" value="63.84.95.4;162.40.107.4;207.5.114.131;216.69.96.174"/>
      <!-- Set the ledger that the ar_text_mstr/dtl records will be setup with. -->
      <add key="Ledger" value="GL"/>
    </appSettings>

Answer 1

The location tag contains values that override other web.config settings when the path attribute contains the requested page. In most scenarios we don't need to put appSettings inside of it. It's better to put all settings in the top-level appSettings element and only put them in a location element if we need to override them for pages within a particular path.

In this case there is only one appSettings element with values, and it's inside this tag:

<location path="Services/Facts">
    <appSettings>
         <add key="DisableSecurity" value="false"/>
         <!-- other settings -->
    </appSettings>
</location>

That means that those settings only "exist" if the requested page is in the /services/facts folder.

If you need an appSettings element that's available to any page, just create one "up a level" in the configuration element:

<configuration>
    <appSettings>
         <add key="YourSetting" value="false"/>
         <!-- other settings -->
    </appSettings>
</configuration>

Now it will always be accessible regardless of what page (or other part of the application) you're in.

---

I don't see this used much with appSettings , although that might just be me. I can see some room for confusion because many developers will assume that if there is a "root" appSettings section, those values will never, ever change while the application is running, and they might store them in a string for some reason (although there's usually no reason to do that.) They might not realize that there are other appSettings inside location tags, and that the first value they read might get reused for other pages in different paths. Or someone could add a location\\appSettings later and it wouldn't work.

I guess the conclusion that leads me to is not that location\\appSettings is bad, but that we should always make sure we're reading settings on every request and not storing them in a variable that gets reused between requests.

---

Technically most of the appSettings sections shown in your web.config don't matter, because they're empty.

<appSettings/>