How are COM classes (generated as structs) meant to be used?

[jnm2]

Using 0.1.506-beta, I couldn't figure out how to use the generated ShellLink struct other than by stringing together Activator.CreateInstance, Type.GetTypeFromCLSID, and typeof(ShellLink).GUID. Is this the intended usage? Is nicer syntax thinkable?

NativeMethods.txt

IPersistFile
IShellLinkW
ShellLink

Utils.cs

using System;
using System.IO;
using Windows.Win32;
using Windows.Win32.System.Com;
using Windows.Win32.UI.Shell;

public static class Utils
{
    public static void CreateShortcut(string shortcutPath, string targetPath)
    {
        var shellLink = (IShellLinkW)Activator.CreateInstance(Type.GetTypeFromCLSID(typeof(ShellLink).GUID, throwOnError: true)!)!;

        shellLink.SetPath(targetPath);
        shellLink.SetWorkingDirectory(Path.GetDirectoryName(targetPath)!);

        ((IPersistFile)shellLink).Save(shortcutPath, fRemember: false);
    }
}

ShellLink.g.cs contains:

[Guid("00021401-0000-0000-C000-000000000046")]internal partial struct ShellLink
{
}

[jnm2]

I was able to achieve this syntax and it ran successfully, so this is at least an option to consider:

public static void CreateShortcut(string shortcutPath, string targetPath)
{
    var shellLink = new IShellLinkW();

    shellLink.SetPath(targetPath);
    shellLink.SetWorkingDirectory(Path.GetDirectoryName(targetPath)!);

    ((IPersistFile)shellLink).Save(shortcutPath, fRemember: false);
}

To make this work, all I had to do was apply [CoClass(typeof(ShellLink))] to IShellLinkW and change the declaration of ShellLink to this:

[ComImport, Guid("00021401-0000-0000-C000-000000000046")]
// Only one or the other of these following attributes seems to be needed.
[ClassInterface(ClassInterfaceType.None)]
[TypeLibType(TypeLibTypeFlags.FCanCreate)]
internal class ShellLink { }

The new IShellLinkW() syntax requires having something present in the metadata relating IShellLinkW to ShellLink. If that's not possible, or if the syntax below is more desirable, the same ShellLink definition above can be used without adding a CoClass attribute to IShellLinkW to enable this syntax which I also ran successfully:

public static void CreateShortcut(string shortcutPath, string targetPath)
{
    var shellLink = (IShellLinkW)new ShellLink();

    shellLink.SetPath(targetPath);
    shellLink.SetWorkingDirectory(Path.GetDirectoryName(targetPath)!);

    ((IPersistFile)shellLink).Save(shortcutPath, fRemember: false);
}

[jnm2]

@AArnott I'd be willing to contribute this fix. Should I convert this discussion to an issue?

[AArnott]

We have talked internally about how to make such scenarios easier. The method you suggest aligns with one of the options we discussed, I think. But this isn't an area I have a lot of expertise in yet, so I'd like to hold off till I get some ratifying votes from MS folks that are more familiar with this area.

Yes, go ahead and convert to (or file) an issue so we can track better.

[jnm2]

I forgot to create an issue, but one just showed up: #453