Unloading resources loaded at run-time

[Vitani]

Hi,

I've got a program that uses plugin DLLs. At the moment they load fine, and work wonderfully. However the whole reason for using plugins is that you can work on one, make changes, and reload it while the main application is still running.

My problem is when I unload the plugins, the accociated dlls are still "locked" to the program, and can't be deleted or overwritten.

Here's how I'm doing it:

using System;
using System.Data;
using System.Data.OleDb;
using System.IO;
using System.Reflection;
using System.Windows.Forms;

.
.
.

    public void load_plugins() {

      Interfaces.Plugin plugin;
      Type[] ObjType = null;
      DirectoryInfo dir = new DirectoryInfo("plugins");
      FileInfo[] arrFilename = dir.GetFiles("*.dll");
      string filename = "";

      foreach (FileInfo f in arrFilename) {

        filename = "plugins\\\\" + f.Name;

        try  {
          // load a single dll
          Assembly asm = null;
          asm = Assembly.LoadFrom(filename);
          if (asm != null) {
            // create an array of types
            ObjType = asm.GetTypes();
          }

        } catch (Exception ex) {
          MessageBox.Show("An error occured while trying to load '" + filename + "': " + ex.Message);
        }

        try  {
          // We need to find all classes that implement the Plugin interface
          if (ObjType != null) {
            // lets loop through each type in our array of types in the loaded dll
            foreach(Type pluginImplemented in ObjType) {

              // If the plugin interface is bound to one of the types, then that type
              // is a class that implements Interfaces.Plugin.
              if(pluginImplemented.GetInterface("Interfaces.Plugin") != null) {

                plugin = (Interfaces.Plugin)Activator.CreateInstance(pluginImplemented);

                if (plugin.Initialize(CarrotzBot, dbCon)) {
                  CarrotzBot.plugins.Add(plugin);

                } else {
                  MessageBox.Show("Failed to Initialize: " + plugin.Name());

                } // end of initilize check

              } // end of is plugin check

            } // end of foreach type loop

          } // end of ObjType check

        } catch (Exception ex) {
          MessageBox.Show("An error occured while trying to initialize '" + filename + "': " + ex.Message);

        } // end of error checking

      } // end of foreach file loop

      this.btnPlugins.Text = "Unload Plugins";

    } // end of load_plugins()

    public void unload_plugins() {
      Interfaces.Plugin plugin;
      int i;
      int plugins = CarrotzBot.plugins.Count;
      
      for (i = 0; i < plugins; i++) {
        plugin = CarrotzBot.plugins[0];
        unload_plugin(plugin);
        
      }
      
    }

    public void unload_plugin(Interfaces.Plugin plugin) {

      plugin.Shutdown();
      CarrotzBot.plugins.Remove(plugin);

      if (CarrotzBot.plugins.Count == 0)
        this.btnPlugins.Text = "Load Plugins";
      
    } 

load_plugins() work fine, and loads the plugins into the program, and they can be used/called sucessfully.
unload_plugins() is a quick way to unload all the plugins that are loaded, this works in that it calls unload_plugin() for each loaded plugin
unload_plugin() shuts down the plugin, and removes it from the collection, however the dll accosiated with it is still open by the application, and can't be deleted/mopved/overwritten. However it can be renamed.

So my question is, how do I unload a plugin, loaded in runtime, so that it releases the dll it lives in?



[Edit: Oooh, just realised, this is my 100th post! Rah!! And it's only taken me 2 years!!]

[Cander]

Sent you a PM.

[PT Exorcist]

hmm i'd like to know to! can u say it cander plz?