Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>your message handlers can be seen as plugins which makes your problem a potential fit for the <a href="http://mef.codeplex.com/wikipage?title=Overview&amp;referringTitle=Home" rel="nofollow noreferrer">Managed Extensibility Framework</a>. Since .Net 4 it's also shipped with the .Net framework.</p> <p>You can find sample introductions to MEF <a href="http://blogs.msdn.com/b/brada/archive/2009/07/20/simple-example-using-managed-extensibility-framework-in-silverlight.aspx" rel="nofollow noreferrer">here</a> and <a href="http://randomactsofcoding.blogspot.com/2009/11/introduction-to-mef.html" rel="nofollow noreferrer">here</a>.</p> <p>I've put together a litte example to show that it's quite simple to use basic MEF functionality (although there is much more you can do with it). First there is a <code>PluginHost</code> class which will host the plugins in its <code>Plugins</code> collection. Then there's a simple interface containing just the property <code>Description</code> and an example implementation of a plugin called <code>ExamplePlugin</code>.</p> <p>The <code>Plugins</code> collection will be filled by the <code>container.ComposeParts(..)</code> method called in the constructor. All that's required to make that magic happen are the <code>[Export]</code> and <code>[ImportMany]</code> attributes.</p> <pre><code>using System; using System.Collections.Generic; using System.ComponentModel.Composition; using System.ComponentModel.Composition.Hosting; namespace Playground { public class Program { static void Main(string[] args) { PluginHost host = new PluginHost(); host.PrintListOfPlugins(); Console.ReadKey(); } } public class PluginHost { [ImportMany] public IEnumerable&lt;IPlugin&gt; Plugins { get; set; } public PluginHost() { var catalog = new AssemblyCatalog(System.Reflection.Assembly.GetExecutingAssembly()); var container = new CompositionContainer(catalog); container.ComposeParts(this); } public void PrintListOfPlugins() { foreach (IPlugin plugin in Plugins) Console.WriteLine(plugin.Description); } } public interface IPlugin { string Description { get; } } [Export(typeof(IPlugin))] public class ExamplePlugin : IPlugin { #region IPlugin Members public string Description { get { return "I'm an example plugin!"; } } #endregion } } </code></pre> <p>UPDATE: You can use so called <a href="http://mef.codeplex.com/wikipage?title=Using%20Catalogs&amp;referringTitle=Guide" rel="nofollow noreferrer">Catalogs</a> to discover plugins in more than one assembly. For example there is a <code>DirectoryCatalog</code> which gives you all exports found in all assemblies in a given directory.</p> <p><code>AppDomain.CurrentDomain.GetAssemblies();</code> returns an array of all assemblies loaded into the current AppDomain. You could then iterate over that array to create an AggregateCatalog containing an AssemblyCatalog per loaded assembly.</p>
    singulars
    1. This table or related slice is empty.
    1. POProblem with Order of "Registration" of .NET Classes in a Messaging Scenario
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USandyp
    1. USandyp
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COI guess I'll have to look at it, but I was hoping not to have to learn another framework.
      singulars
      1. PO
      1. USLimited Atonement
    2. COIt's actually not very hard. Essentially you have to add some attributes to your methods and call a framework method to resolve the exports.
      singulars
      1. PO
      1. USandyp
    3. COSo basically, it looks like this approach uses Reflection in coordination with Attributes to register the plugins. Of course, there are lots of bells and whistles that are added by using the MEF, but all I'm wanting is an automated way to register the plugins without putting burden on the developer. Thanks for the example.
      singulars
      1. PO
      1. USLimited Atonement
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload