Open an admin screen in a tab of the content editor

Here is the method to open a tab in the content editor and display an aspx page in it.
Here is an example:

1. The first you will need is a command. You can add it into your command.config, or in a separate .config in \App_config\Include\. In my example my command is named “commentandrate:opencommenteditoverview” but you can name it as you want of course.

   <configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
     <sitecore>
       <commands>
         <command name="commentandrate:opencommenteditoverview" type="MyNamespace.OpenCommentEditOverView, MyDllName"/>      
       </commands>
     </sitecore>
   </configuration>

2. After that you will only need to write the corresponding class:

   using Sitecore;
   using Sitecore.Diagnostics;
   using Sitecore.Resources;
   using Sitecore.Shell.Framework.Commands;
   using Sitecore.Text;
   using Sitecore.Web;
   using Sitecore.Web.UI.Framework.Scripts;
   using Sitecore.Web.UI.Sheer;
   using Sitecore.Web.UI.XamlSharp.Continuations;
   
   namespace MyNamespace
   {
       public class OpenCommentEditOverView : Command, ISupportsContinuation
       {
           // Methods
           public override void Execute(CommandContext context)
           {
               Assert.ArgumentNotNull(context, "context");
               if (context.Items.Length == 1)
               {
       //Check if the tab is already open and refresh it is needed
                   if (WebUtil.GetFormValue("scEditorTabs").Contains("commentandrate:opencommenteditoverview"))
                   {
                       SheerResponse.Eval("scContent.onEditorTabClick(null, null, 'OpenCommentEditOverView')");
                   }
                   else //Open a new tab
                   {
        //The Path to the aspx file to dsplay in this tab
                       UrlString urlString = new UrlString("/sitecore/shell/Applications/LBi/CommentEditOverView.aspx");
                       context.Items[0].Uri.AddToUrlString(urlString);
                       UIUtil.AddContentDatabaseParameter(urlString);
                       //urlString["fld"] = "__Tracking";
                       SheerResponse.Eval(new ShowEditorTab
                           {
                               Command = "commentandrate:opencommenteditoverview",
                               Header = "Comments", 
                               Icon = Images.GetThemedImageSource("Network/16x16/lock.png"), 
                               Url = urlString.ToString(), 
                               Id = "OpenCommentEditOverView", 
                               Closeable = true
                           }.ToString());
                   }
               }
           }
   
       }
   }

That is it for the command and the code itself but of course you will need a way to call the command.
You can for example add a button in a toolbar.
If you don’t know what is a chunk, a strip, … please refer to this post: http://sitecoreblog.blogspot.be/2010/11/use-contextual-button.html

To create this new button:

1. Switch to the core database
2. In /sitecore/content/Applications/Content Editor/Ribbons/Chunks, add a new “Chunk” (template: /sitecore/templates/System/Ribbon/Chunk)
3. Fill in the fields:
   1. Header: The name who will appear below the block of button
   2. ID: an ID
4. Below this chunk, add a new item of type /sitecore/templates/System/Ribbon/Large Button
5. Fill in the fields:
   1. Header: The name who will appear below the block of button
   2. Icon: The icon of this button
   3. Click: you command name (as in the .config)
   4. Tooltip: the text when you let the mouse on this button
6. To include this chunk in the “Home” toolbar, go in /sitecore/content/Applications/Content Editor/Ribbons/Strips/Home
7. Add a new subitem (template: /sitecore/templates/System/Reference)
8. And fill in the Reference field (example of value: sitecore/content/Applications/Content Editor/Ribbons/Chunks/Comment Rate Admin)