如何在DragDrop特殊文件夹时得到相关信息

今天在论坛看到一个贴子，问如何知道在拖放<我的电脑>

http://social.microsoft.com/Forums/zh-CN/visualcshartzhchs/thread/2a4fc136-3d57-4c64-87de-f19aa9a76d0e/

 

试了一下。发现DragEventArgs.Data可以得到"Shell IDList Array"格式的数据，它实际指向一个CIDA structurer

http://msdn.microsoft.com/en-us/library/bb773212.aspx

通过它，我们就可以得到对应的PIDL （如果对 PIDL 不熟悉，请看Windows外壳名字空间的浏览）。

有了PIDL, 我们就和容易得到文件的相关信息。

 

[DllImport( " shell32.dll " )]
         public   static   extern  IntPtr ILCombine(
            IntPtr pidl1, IntPtr pidl2);


        [DllImport( " shell32.dll " )]
         public   static   extern   void  ILFree(
            IntPtr pidl);

         public   enum  SFGAO :  uint
        {
            BROWSABLE  =   0x8000000 ,
            CANCOPY  =   1 ,
            CANDELETE  =   0x20 ,
            CANLINK  =   4 ,
            CANMONIKER  =   0x400000 ,
            CANMOVE  =   2 ,
            CANRENAME  =   0x10 ,
            CAPABILITYMASK  =   0x177 ,
            COMPRESSED  =   0x4000000 ,
            CONTENTSMASK  =   0x80000000 ,
            DISPLAYATTRMASK  =   0xfc000 ,
            DROPTARGET  =   0x100 ,
            ENCRYPTED  =   0x2000 ,
            FILESYSANCESTOR  =   0x10000000 ,
            FILESYSTEM  =   0x40000000 ,
            FOLDER  =   0x20000000 ,
            GHOSTED  =   0x8000 ,
            HASPROPSHEET  =   0x40 ,
            HASSTORAGE  =   0x400000 ,
            HASSUBFOLDER  =   0x80000000 ,
            HIDDEN  =   0x80000 ,
            ISSLOW  =   0x4000 ,
            LINK  =   0x10000 ,
            NEWCONTENT  =   0x200000 ,
            NONENUMERATED  =   0x100000 ,
            READONLY  =   0x40000 ,
            REMOVABLE  =   0x2000000 ,
            SHARE  =   0x20000 ,
            STORAGE  =   8 ,
            STORAGEANCESTOR  =   0x800000 ,
            STORAGECAPMASK  =   0x70c50008 ,
            STREAM  =   0x400000 ,
            VALIDATE  =   0x1000000
        }
         public   const   int  MAX_PATH  =   260 ;


        [StructLayout(LayoutKind.Sequential, CharSet  =  CharSet.Auto)]
         public   struct  SHFILEINFO
        {
             public  IntPtr hIcon;
             public   int  iIcon;
             public  SFGAO dwAttributes;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst  =  MAX_PATH)]
             public   string  szDisplayName;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst  =   80 )]
             public   string  szTypeName;
        }



         public   enum  SHGFI :  uint
        {
            ADDOVERLAYS  =   0x20 ,
            ATTR_SPECIFIED  =   0x20000 ,
            ATTRIBUTES  =   0x800 ,
            DISPLAYNAME  =   0x200 ,
            EXETYPE  =   0x2000 ,
            ICON  =   0x100 ,
            ICONLOCATION  =   0x1000 ,
            LARGEICON  =   0 ,
            LINKOVERLAY  =   0x8000 ,
            OPENICON  =   2 ,
            OVERLAYINDEX  =   0x40 ,
            PIDL  =   8 ,
            SELECTED  =   0x10000 ,
            SHELLICONSIZE  =   4 ,
            SMALLICON  =   1 ,
            SYSICONINDEX  =   0x4000 ,
            TYPENAME  =   0x400 ,
            USEFILEATTRIBUTES  =   0x10
        }


         public   enum  FILE_ATTRIBUTE
        {
            READONLY  =   0x00000001 ,
            HIDDEN  =   0x00000002 ,
            SYSTEM  =   0x00000004 ,
            DIRECTORY  =   0x00000010 ,
            ARCHIVE  =   0x00000020 ,
            DEVICE  =   0x00000040 ,
            NORMAL  =   0x00000080 ,
            TEMPORARY  =   0x00000100 ,
            SPARSE_FILE  =   0x00000200 ,
            REPARSE_POINT  =   0x00000400 ,
            COMPRESSED  =   0x00000800 ,
            OFFLINE  =   0x00001000 ,
            NOT_CONTENT_INDEXED  =   0x00002000 ,
            ENCRYPTED  =   0x00004000
        }


        [DllImport( " shell32 " ,
            EntryPoint  =   " SHGetFileInfo " ,
            ExactSpelling  =   false ,
            CharSet  =  CharSet.Auto,
            SetLastError  =   true )]
         public   static   extern  IntPtr SHGetFileInfo(
            IntPtr ppidl,
            FILE_ATTRIBUTE dwFileAttributes,
             ref  SHFILEINFO sfi,
             int  cbFileInfo,
            SHGFI uFlags);


protected   override   void  OnDragDrop(DragEventArgs drgevent)
        {
             base .OnDragDrop(drgevent);
            
            
            MemoryStream data  =  (MemoryStream)drgevent.Data.GetData( " Shell IDList Array " );
             byte [] b  =  data.ToArray();
            IntPtr p  =  Marshal.AllocHGlobal(b.Length);
            Marshal.Copy(b,  0 , p, b.Length);


             //  Get number of items. 
            UInt32 cidl  =  (UInt32)Marshal.ReadInt32(p);
                                     
             int  offset  =   sizeof (UInt32);
            IntPtr parentpidl  =  (IntPtr)(( int )p  +  (UInt32)Marshal.ReadInt32(p, offset));
            

             //  Get subitems. 
             for  ( int  i  =   1 ; i  <=  cidl;  ++ i)
            {
                offset  +=   sizeof (UInt32);
                IntPtr relpidl  =  (IntPtr)(( int )p  +  (UInt32)Marshal.ReadInt32(p, offset));
                IntPtr abspidl  =  ILCombine(parentpidl, relpidl);
                SHFILEINFO sf = new  SHFILEINFO();
                 if  (SHGetFileInfo(abspidl,  0 ,  ref  sf, Marshal.SizeOf(sf), SHGFI.PIDL  |  SHGFI.DISPLAYNAME  |  SHGFI.TYPENAME).ToInt32() > 0 )
                {
                    MessageBox.Show(sf.szDisplayName);
                }

                ILFree(abspidl);



            }

        }