reflection for plug in

Tech-Archive recommends: Fix windows errors by optimizing your registry

Hi all,

I am trying to create a plug-in handler that discovers and enumerates my plug-ins at runtime. I've got it working, but I had to defensively trap and swallow a lot of exceptions. Is there a better way to discover if an executable is a valid assembly? Is there a better way to discover is an assembly has a particular type?

Please see the code below that I am using to discover types in a directory and add the valid assemblies to a list.

Thanks,
Scott

private void GetAvailableAnalysis()
{
Debug.Assert(m_PathToAnalysis != null);

string appPath = Path.GetDirectoryName(m_PathToAnalysis);
string[] files = Directory.GetFiles(appPath, "*.exe");
m_AnalysisNames.Clear();
m_AssemblyNames.Clear();

if (files != null )
{
foreach (string fileName in files)
{
Assembly thisAssembly;
try
{
thisAssembly = Assembly.Load(Path.GetFileNameWithoutExtension(fileName));

if (thisAssembly != null)
{

Debug.WriteLine(string.Format("Assembly: {0}", thisAssembly));

Type[] assemblyTypes = thisAssembly.GetTypes();
Type interfaceType = Type.GetType("AnalysisProxy.IAnalyze");

if (assemblyTypes != null && interfaceType != null)
{
foreach (Type thisType in assemblyTypes)
{
if (interfaceType.IsAssignableFrom(thisType))
{

m_AnalysisNames.Add(thisType.FullName);

m_AssemblyNames.Add(thisAssembly.FullName);


Debug.WriteLine(string.Format("Found IAnalyze in Type: {0}", thisType));
}
else
{

Debug.WriteLine(string.Format("Not IAnalyze Type: {0}", thisType));
}
}
}

}
}
catch (ReflectionTypeLoadException ex)
{
// Swallow the exception. Type was not found.
Debug.WriteLine(string.Format("Type not found in .NET assembly: {0}\n\n{1}", fileName, ex.Message));
}
catch (BadImageFormatException ex)
{
// do nothing, this is just not a .net assembly
Debug.WriteLine(string.Format("Not a .NET assembly: {0}\n\n{1}", fileName, ex.Message));
}
catch (FileLoadException ex)
{

Debug.WriteLine(string.Format("FileLoadException loading: {0}\n\n{1}", fileName, ex.Message));
}
catch (Exception ex)
{
string exceptionMessage = "Error occurred trying to load: " + fileName;
throw new Exception(exceptionMessage, ex.InnerException);
}
}
}
}
.