public string SaveFile()
    {
        SaveFileBrowse pth = new SaveFileBrowse();

        pth.structSize = System.Runtime.InteropServices.Marshal.SizeOf(pth);
        //pth.filter = "txt files(.txt)|.txt";
        pth.file         = new string(new char[256]);
        pth.maxFile      = pth.file.Length;
        pth.fileTitle    = new string(new char[64]);
        pth.maxFileTitle = pth.fileTitle.Length;
        pth.initialDir   = Application.dataPath; // default path
        pth.title        = "保存项目";
        pth.defExt       = "txt";
        pth.flags        = 0x00080000 | 0x00001000 | 0x00000800 | 0x00000200 | 0x00000008;
        if (SaveFileDialog.GetSaveFileName(pth))
        {
            string filepath = pth.file;//选择的文件路径;

            File.WriteAllText(filepath, inputText.text);

            return(filepath);
        }

        return("NullPath");
    }
 public static extern bool GetSaveFileName([In, Out] SaveFileBrowse ofd);