COM interface IEnumString to string array

IEnumStringToArray.cs

private string[] IEnumStringToArray(IEnumString enumerator)
{
    const int S_OK = 0x00000000;
    List<string> lst = new List<string>();
    if (enumerator != null)
    {
        int cft;
        string[] strF = new string[100];
        int hresult;
        IntPtr intPtr = Marshal.AllocCoTaskMem(sizeof(int));
        try
        {
            do
            {
                hresult = enumerator.Next(100, strF, intPtr);
                if (hresult < 0)
                    Marshal.ThrowExceptionForHR(hresult);
                cft = Marshal.ReadInt32(intPtr);
                if (cft > 0)
                {
                    for (int i = 0; i < cft; i++)
                        lst.Add(strF[i]);
                }
            }
            while (hresult == S_OK);
        }
        finally
        {
            if (intPtr != IntPtr.Zero)
                Marshal.FreeCoTaskMem(intPtr);
        }
    }
    return lst.ToArray();
}