Application Specific Paths for DLL Loading when DLL is loaded dynamically
- by MartinHT
Hi:
I am building a program that uses a very simple plugin system. This is the code I'm using to load the possible plugins:
public interface IPlugin
{
string Name { get; }
string Description { get; }
bool Execute(System.Windows.Forms.IWin32Window parent);
}
private void loadPlugins()
{
int idx = 0;
string[] pluginFolders = getPluginFolders();
Array.ForEach(pluginFolders, folder =>
{
string[] pluginFiles = getPluginFiles(folder);
Array.ForEach(pluginFiles, file =>
{
try
{
System.Reflection.Assembly assembly = System.Reflection.Assembly.LoadFile(file);
Array.ForEach(assembly.GetTypes(), type =>
{
if(type.GetInterface("PluginExecutor.IPlugin") != null)
{
IPlugin plugin = assembly.CreateInstance(type.ToString()) as IPlugin;
if(plugin != null)
lista.Add(new PluginItem(plugin.Name, plugin.Description, file, plugin));
}
});
}
catch(Exception) { }
});
});
}
When the user selects a particular plugin from the list, I launch the plugin's Execute method. So far, so good! As you can see the plugins are loaded from a folder, and within the folder are several dll's that are needed but the plugin. My problem is that I can't get the plugin to 'see' the dlls, it just searches the launching applications startup folder, but not the folder where the plugin was loaded from.
I have tried several methods:
1. Changing the Current Directory to the plugins folder.
2. Using an inter-op call to SetDllDirectory
3. Adding an entry in the registry to point to a folder where I want it to look (see code below)
None of these methods work. What am I missing? As I load the dll plugin dynamically, it does not seem to obey any of the above mentioned methods. What else can I try?
Regards,
MartinH.
//HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths
Microsoft.Win32.RegistryKey appPaths = Microsoft.Win32.Registry.LocalMachine.CreateSubKey(
string.Format(
@"SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\{0}",
System.IO.Path.GetFileName(Application.ExecutablePath)),
Microsoft.Win32.RegistryKeyPermissionCheck.ReadWriteSubTree);
appPaths.SetValue(string.Empty, Application.ExecutablePath);
object path = appPaths.GetValue("Path");
if(path == null)
appPaths.SetValue("Path", System.IO.Path.GetDirectoryName(pluginItem.FileName));
else
{
string strPath = string.Format("{0};{1}", path, System.IO.Path.GetDirectoryName(pluginItem.FileName));
appPaths.SetValue("Path", strPath);
}
appPaths.Flush();
