Unable to delete assembly (.exe)

Question

I've written a small app to get version numbers of files contained within a .cab file.

I extract all files from the cab to a temp directory and loop through all the files and retrieve version numbers as follows:

//Attempt to load .net assembly to retrieve information
Assembly assembly = Assembly.LoadFile(tempDir + @"\" + renameTo);
Version version = assembly.GetName().Version;
DataRow dr = dt.NewRow();
dr["Product"] = renameTo;
dr["Version"] = version.ToString();
dt.Rows.Add(dr); 

Then when finished I want to delete all the files that have been extracted as follows:

        foreach (string filePath in filePaths)
        {
            //Remove read-only attribute if set
            FileAttributes attributes = File.GetAttributes(filePath);

            if ((attributes & FileAttributes.ReadOnly) == FileAttributes.ReadOnly)
            {
                File.SetAttributes(filePath, attributes ^ FileAttributes.ReadOnly);
            }

            File.Delete(filePath);
        }

This works for all files except except sometimes fails on .net .exe's. I can manually delete the file so it does not appear to be locked.

What should I be looking for to make this work? Is Assembly.LoadFile perhaps locking the file?

Answer 1

Assembly.LoadFile does indeed lock the file. If you need to load assemblies from files and then subsequently delete the files, what you need to do is:

1. Start a new AppDomain
2. Load the assembly in that appdomain
3. Only work with it there- do not use any types from the assembly in your main appdomain.
4. Call AppDomain.Unload to tear down the AppDomain
5. Then delete the file

You cannot delete a file containing an assembly while that assembly is loaded into an executing AppDomain.

Answer 2

AssemblyName.GetAssemblyName will get the AssemblyName object without locking the file on you. see msdn. You can get the version from there.