C# 打开目录，且同一目录不重复打开新窗口

针对同一目录不重复打开新窗口

两种方法：

第一种，仅打开目录

static public class Win32Help
{
        public enum ShowCommands : int
        {
            SW_HIDE = 0,
            SW_SHOWNORMAL = 1,
            SW_NORMAL = 1,
            SW_SHOWMINIMIZED = 2,
            SW_SHOWMAXIMIZED = 3,
            SW_MAXIMIZE = 3,
            SW_SHOWNOACTIVATE = 4,
            SW_SHOW = 5,
            SW_MINIMIZE = 6,
            SW_SHOWMINNOACTIVE = 7,
            SW_SHOWNA = 8,
            SW_RESTORE = 9,
            SW_SHOWDEFAULT = 10,
            SW_FORCEMINIMIZE = 11,
            SW_MAX = 11
        }

        [DllImport("shell32.dll")]
        public static extern IntPtr ShellExecute(IntPtr hwnd, string lpOperation, string lpFile, string lpParameters, string lpDirectory, ShowCommands nShowCmd);
}

//调用

        static public void OpenFolder(string fileFullName) => Win32Help.ShellExecute(IntPtr.Zero, "open", fileFullName, "", "", Win32Help.ShowCommands.SW_SHOWNORMAL);

第二种，打开目录并选中指定文件

[DllImport("shell32.dll", ExactSpelling = true)]
public static extern void ILFree(IntPtr pidlList);

[DllImport("shell32.dll", CharSet = CharSet.Unicode, ExactSpelling = true)]
public static extern IntPtr ILCreateFromPathW(string pszPath);

[DllImport("shell32.dll", ExactSpelling = true)]
public static extern int SHOpenFolderAndSelectItems(IntPtr pidlList, uint cild, IntPtr children, uint dwFlags);



        /// <summary>
        /// 打开指定文件夹并选中相应文件
        /// </summary>
        /// <param name="fileFullName">目录或文件路径</param>
        /// <returns></returns>
        internal static bool SelectInFileExplorer(this string fileFullName)
        {
            if (fileFullName.IsNullOrEmpty())
                throw new ArgumentNullException(nameof(fileFullName));
            fileFullName = System.IO.Path.GetFullPath(fileFullName);
            var pidlList = Win32Help.ILCreateFromPathW(fileFullName);
            if (pidlList == IntPtr.Zero) return false;
            try
            {
                Marshal.ThrowExceptionForHR(Win32Help.SHOpenFolderAndSelectItems(pidlList, 0, IntPtr.Zero, 0));
                return true;
            }
            catch (Exception e)
            {
                return false;
            }
            finally
            {
                Win32Help.ILFree(pidlList);
            }
        }

//调用

        /// <summary>
        /// 打开目录并选中相应文件
        /// </summary>
        /// <param name="fileFullName"></param>
        static public void OpenFolderAndSelectFile(string fileFullName) => Win32Help.SelectInFileExplorer(fileFullName);