C# configSections "Sections must only appear once per config file."

Question

I want to create a "List" of clientUsers that contains many of clientUser

 <configuration>
        <configSections>
          <sectionGroup name="clientUsers">
            <section name="clientUser" type="System.Configuration.NameValueFileSectionHandler" />
          </sectionGroup>
        </configSections>

        <clientUsers>
            <!-- user number 1  -->
            <clientUser>
              <add key="id"       value="1" />
              <add key="userName" value="someuser" />
              <add key="password" value="test" />
              <add key="IPs"      value="1,2,3" />
            </clientUser>

            <!-- user number 2  -->
            <clientUser>
              <add key="id"       value="2" />
              <add key="userName" value="avi2" />
              <add key="password" value="test" />
              <add key="IPs"      value="1,2,3" />
            </clientUser>
   </clientUsers>

Why do i get this error:

Sections must only appear once per config file. See the help topic for exceptions.

How do I create a list of clientUser

The comments in your XML are actually written like that in your file? If they are, change // for — Icarus, Oct 06 '11 at 11:20
You are getting the error for exactly the reason it says. **ClientUser** is only allowed to be in the file once. — Security Hound, Oct 06 '11 at 11:26
@Ramhound - Do you have any idea how annoying is your comment ??? I am asking how to create a list of ClientUser. — SexyMF, Oct 06 '11 at 11:28
I think there are similar questions asked already. Check the answer to [this question](https://stackoverflow.com/questions/710449/accessing-a-custom-configuration-section-in-net). He did it with a custom configuration handler. — Andreas, Oct 06 '11 at 11:38
Thanks but it is not the same... see my structure, it is different. thanks — SexyMF, Oct 06 '11 at 11:41
@SexyMF: yes, that's what you need. You will not be able to have exactly that structure in your config file, but you will only need to add a node. Otherwise, remove the sectionGroup, which is not mandatory, and call your configSection `clientUsers`, and have it contain sever `clientUser` objects. — Paolo Tedesco, Oct 06 '11 at 11:46
@SexyMF I guess you have to change your structure. I looked over his answer and I think it's everything you need to solve your issue. — Andreas, Oct 06 '11 at 12:06

score 1 · Answer 1 · answered Oct 06 '11 at 11:47

I think you are looking for ConfigurationElementCollection class under System.Configuration MSDN Link http://msdn.microsoft.com/en-us/library/system.configuration.configurationelementcollection.aspx

There is also a tutoial on codeproject

A short snippet from the codeproject site

public class ShiSettingCollection : ConfigurationElementCollection
   {
      public ShiSettingElements this[int index]
      {
         get
         {
            return base.BaseGet(index) as ShiSettingElements;
         }
         set
         {
            if (base.BaseGet(index) != null)
            {
               base.BaseRemoveAt(index);
            }
            this.BaseAdd(index, value);
         }
      }
      protected override System.Configuration.ConfigurationElement CreateNewElement()
      {
         return new ShiSettingElements();
      }

      protected override object GetElementKey(ConfigurationElement element)
      {
         return ((ShiSettingElements)element).Key;
      }
   }

C# configSections "Sections must only appear once per config file."

1 Answers1