How to convert C# String[] to PCWSTR* for using by PInvoke.InitPropVariantFromStringVector

[harborsiem]

What is the best way to convert a String array to a PCWSTR* for using by PInvoke.InitPropVariantFromStringVector(PCWSTR*, uint, out PROPVARIANT) function?

I have done it this way with GCHandle pinning for every String.

/// <summary>
/// Converts a string array to a PROPVARIANT
/// with pinned strings, so the GC can't move the strings in memory till PInvoke function is called
/// </summary>
/// <param name="strings"></param>
/// <param name="propVar"></param>
/// <returns></returns>
internal static unsafe HRESULT InitPropVariantFromStringVector(string[] strings, out PROPVARIANT propVar)
{
    HRESULT hr;
    PCWSTR[] array = new PCWSTR[strings.Length];
    GCHandle[] pins = new GCHandle[strings.Length];
    for (int i = 0; i < array.Length; i++)
    {
        if (strings[i] != null)
           pins[i] = GCHandle.Alloc(strings[i], GCHandleType.Pinned);
        else
           pins[i] = GCHandle.Alloc(string.Empty, GCHandleType.Pinned);
        array[i] = (char*)pins[i].AddrOfPinnedObject();
    }
    fixed (PCWSTR* parray = array)
        hr = PInvoke.InitPropVariantFromStringVector(parray, (uint)strings.Length, out propVar);
    for (int i = 0; i < pins.Length; i++)
    {
        if (pins[i].IsAllocated)
            pins[i].Free();
    }
    return hr;
}

[AArnott]

That's a good approach, IMO. I would add try/finally blocks to ensure that an exception thrown wouldn't leak memory, but otherwise it's decent.

[xyzzer]

Is there any sort of "getting started" in the works? I've been using basic pinvoke for years without issues, without pinning anything manually. I'm sure there are benefits to this more verbose approach, but this seems like something that should be listed in the main README.md :)

[AArnott]

That's a good idea. Nothing in the works at present though.