Referencing shell32 again, C# Visual Studio

Question

Hmmm. Okay after revisiting PInvoke, I'm sure that I don't quite get it :-/ (just asked this question)

Let me illustrate the code I need to handle. It works when I use "Add Reference --> COM --> Microsoft Shell Controls and Automatation" ... but sadly it places a reference in my project that looks like this: "C:\Users\Tim\Documents\Visual Studio 2008\Projects\Wing\FileWing\obj\Debug\Interop.Shell32.dll"

I'm digging though the recycling bin and seek for a item that I want to recover. Is there any way NOT fighting through the PInvoke to get this done? Or to get a reference to the system32/shell32.dll that lets me use this code at runtime?

private void recoverRecyclerBinEntry(string fileName, int size)
{
    try
    {
        Shell Shl = new Shell();
        Folder Recycler = Shl.NameSpace(10);

        // scans through all the recyclers entries till the one to recover has been found
        for (int i = 0; i < Recycler.Items().Count; i++)
        {
            FolderItem FI = Recycler.Items().Item(i);
            string FileName = Recycler.GetDetailsOf(FI, 0);
            if (Path.GetExtension(FileName) == "")
                FileName += Path.GetExtension(FI.Path);
            //Necessary for systems with hidden file extensions.

            string FilePath = Recycler.GetDetailsOf(FI, 1);
            string combinedPath = Path.Combine(FilePath, FileName);

            if (size == FI.Size && fileName == combinedPath)
            {
                Debug.Write("Match found. Restoring " + combinedPath + "...");
                Undelete(FI);
                Debug.WriteLine("done.");
            }
            else
            {
                Debug.WriteLine("No match");
            }
        }
    } 
    catch (Exception ex)
    {
        Debug.WriteLine(ex.Message);
        Debug.WriteLine(ex.StackTrace);
    }
}

private bool Undelete(FolderItem Item)
{
    try
    {
        foreach (FolderItemVerb FIVerb in Item.Verbs())
        {
            if (
                (FIVerb.Name.ToUpper().Contains("WIEDERHERSTELLEN")) ||
                (FIVerb.Name.ToUpper().Contains("ESTORE")) ||
                (FIVerb.Name.ToUpper().Contains("NDELETE"))
                )
            {
                FIVerb.DoIt();
                return true;
            }
        }
        //execute the first one:
        Item.Verbs().Item(0).DoIt();
        return true;
    }
    catch (Exception)
    {
        Debug.WriteLine("ERROR undeleting");
        return false;
    }
}

Answer 1

Right now you're mixing 2 different concepts: PInvoke and COM Interop.

PInvoke allows you to access native C functions from within managed code. It works by defining a marshal compatible signature of the native method in managed code and marking it with the DllImport attribute. It requires, and cannot have, a metadata reference to the native DLL. The DLL is discovered at runtime using normal loading rules for a Win32 DLL.

COM Interop allows you to access COM compatible objects from managed code. This is done by getting a marshal compatible managed definition of the COM interface and then gaining a referece to the object in one of several ways. Getting the managed definition is often accomplished by means of adding a metadata reference to the PIA (primary interop assembly) for the COM component. Until C# 4.0, this reference cannot be removed, without a lot of work, and must be deployed with your application.

In this particular example you are using COM interop and not PInvoke.