This sample code illustrates how to create a tree structure in C1:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Composite.C1Console.Elements;
using Composite.C1Console.Elements.Plugins.ElementProvider;
using Composite.C1Console.Security;
using Composite.C1Console.Security.SecurityAncestorProviders;
using Composite.Core.ResourceSystem.Icons;


namespace MyCode
{
  public sealed class EnvironmentPropertiesElementProvider : IHooklessElementProvider, IAuxiliarySecurityAncestorProvider
  {
    private EnvironmentPropertiesElements _environmentPropertiesElements;

    private IEnumerable<Element> Roots
    {
      get
      {
        yield return _environmentPropertiesElements.EnvironmentElement;
      }
    }

    public EnvironmentPropertiesElementProvider()
    {
      AuxiliarySecurityAncestorFacade.AddAuxiliaryAncestorProvider<EnvironmentEntityToken>(this);
    }

    public ElementProviderContext Context
    {
      set
      {
        _environmentPropertiesElements = new EnvironmentPropertiesElements(value);
      }
    }

    public IEnumerable<Element> GetChildren(EntityToken entityToken, SearchToken seachToken)
    {
      if (entityToken.Id == _environmentPropertiesElements.EnvironmentElementId.ToString())
      {
        yield return _environmentPropertiesElements.OSVersionElement;
        yield return _environmentPropertiesElements.ProcessorCountElement;
      }
      yield break;
    }

    public IEnumerable<Element> GetRoots(SearchToken seachToken)
    {
      return Roots;
    }

    public Dictionary<EntityToken, IEnumerable<EntityToken>> GetParents(IEnumerable<EntityToken> entityTokens)
    {
      var result = new Dictionary<EntityToken, IEnumerable<EntityToken>>();

      foreach (EntityToken entityToken in entityTokens)
      {
        if (entityToken.Id == _environmentPropertiesElements.EnvironmentElementId.ToString())
          continue;

        result.Add(entityToken, new EntityToken[] { _environmentPropertiesElements.EnvironmentEntityToken });
      }

      return result;
    }
  }


  internal class EnvironmentPropertiesElements
  {
    private ElementProviderContext _providerContext;

    public EnvironmentPropertiesElements(ElementProviderContext value)
    {
      this._providerContext = value;
    }

    public Element EnvironmentElement
    {
      get
      {
        return new Element(_providerContext.CreateElementHandle(EnvironmentEntityToken))
        {
          VisualData = new ElementVisualizedData()
          {
            Label = "Environment",
            ToolTip = "Environment",
            HasChildren = true,
            Icon = CommonElementIcons.Folder,
            OpenedIcon = CommonElementIcons.FolderOpen
          }
        };
      }
    }

    public Element OSVersionElement
    {
      get
      {
        return new Element(_providerContext.CreateElementHandle(new EnvironmentEntityToken("OSVersion")))
        {
          VisualData = new ElementVisualizedData()
          {
            Label = Environment.OSVersion.ToString(),
            ToolTip = "ProcessorCount",
            HasChildren = false,
            Icon = CommonElementIcons.Data,
            OpenedIcon = CommonElementIcons.Data
          }
        };
      }
    }

    public Element ProcessorCountElement
    {
      get
      {
        return new Element(_providerContext.CreateElementHandle(new EnvironmentEntityToken("ProcessorCount")))
        {
          VisualData = new ElementVisualizedData()
          {
            Label = Environment.ProcessorCount.ToString(),
            ToolTip = "ProcessorCount",
            HasChildren = false,
            Icon = CommonElementIcons.Data,
            OpenedIcon = CommonElementIcons.Data
          }
        };
      }
    }

    public EntityToken EnvironmentEntityToken
    {
      get { return new EnvironmentEntityToken(EnvironmentElementId.ToString()); }
    }

    public Guid EnvironmentElementId
    {
      get { return new Guid("{CABEDE97-FB1C-48F5-847D-16C7675EB889}"); }
    }
  }

  [SecurityAncestorProvider(typeof(NoAncestorSecurityAncestorProvider))]
  public class EnvironmentEntityToken : EntityToken
  {
    private string _id;

    public EnvironmentEntityToken(string id)
    {
      _id = id;
    }

    public override string Id
    {
      get { return _id; }
    }

    public override string Serialize()
    {
      return DoSerialize();
    }

    public override string Source
    {
      get { return ""; }
    }

    public override string Type
    {
      get { return ""; }
    }

    public static EntityToken Deserialize(string serializeedEntityToken)
    {
      string type, source, id;
      DoDeserialize(serializeedEntityToken, out type, out source, out id);
      return new EnvironmentEntityToken(id);
    }
  }
}

Download the sample code

To use this sample:

1. Copy this file to /App_Code.
2. Edit Composite.config and locate this element: Composite.C1Console.Elements.Plugins.ElementProviderConfiguration[@rootProviderName="VirtualElementProvider"]/
ElementProviderPlugins/add[@name="VirtualElementProvider"]/VirtualElements.
3. Under this element, add the following:
   

   <add id="SystemPerspective" order="8" parentId="ID01" 
        tag="System" providerName="EnvironmentPropertiesElementProvider" 
        label="${Composite.Management, VirtualElementProviderElementProvider.SystemPerspective}" 
        closeFolderIconName="Composite.Icons.perspective-system" openFolderIconName="" 
        type="Composite.Plugins.Elements.ElementProviders.VirtualElementProvider.ProviderHookingElementConfigurationElement, Composite" 
        name="EnvironmentProperties" />

4. Then, under Composite.C1Console.Elements.Plugins.ElementProviderConfiguration[@rootProviderName="VirtualElementProvider"]/
ElementProviderPlugins, add the following:
   

   <add name="EnvironmentPropertiesElementProvider" 
        type="MyCode.EnvironmentPropertiesElementProvider, App_Code" />

5. Now log in to the C1 Console.
6. Restart the server (Tools | Restart Server).
7. Switch to the System perspective.

There should be a new element: Environment, that has two sub-elements (OS, the number of processor cores).