HOW TO:获取文件扩展属性

Author: 水如烟

Option   Strict   Off

Namespace  uIO

     Public   Class  File

         ' 前期绑定的话需引用COM:Microsoft Shell Controls And Automation
         Public   Shared   Function  GetDetails( ByVal  file  As   String )  As  Dictionary(Of  String ,  Object )
             Dim  mResult  As   New  Dictionary(Of  String ,  Object )


             Dim  mPath  As   String   ' 取文件或目录的路径
             Dim  mFileName  As   String    ' 取文件名或目录名

             If  IO.File.Exists(file)  Then    ' 如是文件
                 Dim  tmpFileInfo  As   New  IO.FileInfo(file)
                 With  tmpFileInfo
                    mPath  =  .DirectoryName
                    mFileName  =  .Name
                 End   With
             Else
                 If  IO.Directory.Exists(file)  Then   ' 如是目录
                     Dim  tmpDirectoryInfo  As   New  IO.DirectoryInfo(file)
                     With  tmpDirectoryInfo
                         If  .Parent  Is   Nothing   Then
                             Throw   New  Exception  ' 不能查询根目录
                         Else
                            mPath  =  .Parent.FullName
                            mFileName  =  .Name
                         End   If
                     End   With
                 Else
                     Throw   New  IO.FileNotFoundException  ' 文件或目录无效
                 End   If
             End   If


             Dim  mShell  As   Object   ' Shell32.Shell '
             Dim  mFolder  As   Object   ' Shell32.Folder
             Dim  mFolderItem  As   Object   ' Shell32.FolderItem

            mShell  =   CreateObject ( " Shell.Application " )  '  New Shell32.Shell '

             ' mFolder = mShell.NameSpace(mPath)
             ' 上语句用WScript解释或引用COM方式都能正常运行, 但后期绑定中返回的是Nothing
             ' 而直接用字符串值代替变量mPath又是能取得正确结果的
             ' 暂用下句代替
            mFolder  =  System.Runtime.CompilerServices.RuntimeHelpers.GetObjectValue(Microsoft.VisualBasic.CompilerServices.NewLateBinding.LateGet(mShell,  Nothing ,  " Namespace " ,  New   Object () {mPath},  Nothing ,  Nothing ,  Nothing ))

            mFolderItem  =  mFolder.ParseName(mFileName)  ' 等效于mFolder.Items.Item(MFileName)

             ' 可能的属性数。一般个数为13,查到扩展属性时是34,这里我加到256
             Dim  mCount  As   Integer   =   & HFF

             Dim  mPropertyName  As   String
             Dim  mPropertyValue  As   Object

             For  i  As   Integer   =   0   To  mCount
                mPropertyName  =  mFolder.GetDetailsOf( Nothing , i)  ' 取属性名称
                mPropertyValue  =  mFolder.GetDetailsOf(mFolderItem, i)  ' 取属性值
                 If   Not  mPropertyName  =   ""   Then
                    mResult.Add(mPropertyName, mPropertyValue)
                 End   If
             Next


            mFolderItem  =   Nothing
            mFolder  =   Nothing
            System.Runtime.InteropServices.Marshal.ReleaseComObject(mShell)
            mShell  =   Nothing

             Return  mResult
         End Function

     End Class

End Namespace

测试,顺便也测试混合格式的处理:

     Private   Sub  Button1_Click( ByVal  sender  As  System.Object,  ByVal  e  As  System.EventArgs)  Handles  Button1.Click
         Dim  mCollection  As  ICollection  =  LzmTW.uIO.File.GetDetails( " d:\lzmtw.dll " )
        LzmTW.uCollection.MoveNext(mCollection,  New  Action(Of KeyValuePair(Of  String ,  Object ))( AddressOf  Printer))
     End Sub

     Public   Sub  Printer( ByVal  KeyValue  As  KeyValuePair(Of  String ,  Object ))
         Static  i  As   Integer
         With  KeyValue
            Console.WriteLine(LzmTW.uString.Format( " {0,-14}:{1,-30}  第{2,2}项 " , .Key, .Value, i))
         End   With
        i  +=   1
     End Sub

其中MoveNext的代码:

     Public   Shared   Sub  MoveNext(Of T)( ByVal  enumerator  As  IEnumerator,  ByVal  action  As  Action(Of T))

         While  enumerator.MoveNext
            action.Invoke( CType (enumerator.Current, T))
         End   While
     End Sub

     Public   Shared   Sub  MoveNext(Of T)( ByVal  collection  As  ICollection,  ByVal  action  As  Action(Of T))

        MoveNext(Of T)(collection.GetEnumerator, action)
     End Sub

     Public   Shared   Sub  MoveNext(Of T)( ByVal  enumerable  As  IEnumerable,  ByVal  action  As  Action(Of T))

        MoveNext(Of T)(enumerable.GetEnumerator, action)
     End Sub

结果,要图片才行: