列舉網路芳鄰的網路資源

jeff — Wed, 23 Apr 2008 19:07:00 GMT

此範例會以遞迴方式列舉網路芳鄰的網路資源，在此範例中會使用到 mpr.dll API 函式庫的 WNetEnumResource、WNetOpenEnum、WNetCloseEnum 函式來進行網路芳鄰的網路資源的列舉動作。

TAPIMpr 類別為 mpr.dll API 函式庫的操作類別

   1:      ''' <summary>

   2:      ''' 網路芳鄰相關函式庫(mpr.dll)。

   3:      ''' </summary>

   4:      Public NotInheritable Class TAPIMpr

   5:          Public Enum EResourceScope As Integer

   6:              ''' <summary>

   7:              ''' 正連線的資源。

   8:              ''' </summary>

   9:              RESOURCE_CONNECTED = &H1

  10:              ''' <summary>

  11:              ''' 網路上所有的資源。

  12:              ''' </summary>

  13:              RESOURCE_GLOBALNET = &H2

  14:              ''' <summary>

  15:              ''' 曾經連線的資源。

  16:              ''' </summary>

  17:              RESOURCE_REMEMBERED = &H3

  18:          End Enum

19:

  20:          Public Enum EResourceType As Integer

  21:              ''' <summary>

  22:              ''' 所有網路資源。

  23:              ''' </summary>

  24:              RESOURCETYPE_ANY = &H0

  25:              ''' <summary>

  26:              ''' 網路磁碟機。

  27:              ''' </summary>

  28:              RESOURCETYPE_DISK = &H1

  29:              ''' <summary>

  30:              ''' 網路印表機。

  31:              ''' </summary>

  32:              RESOURCETYPE_PRINT = &H2

  33:              ''' <summary>

  34:              ''' 未知。

  35:              ''' </summary>

  36:              RESOURCETYPE_UNKNOWN = &HFFFFFFFF

  37:          End Enum

38:

  39:          Public Enum EResourceDisplayType As Integer

  40:              ''' <summary>

  41:              ''' 一般資源。

  42:              ''' </summary>

  43:              RESOURCEDISPLAYTYPE_GENERIC = 0

  44:              ''' <summary>

  45:              ''' 網域資源。

  46:              ''' </summary>

  47:              RESOURCEDISPLAYTYPE_DOMAIN = 1

  48:              ''' <summary>

  49:              ''' 伺服器資源。

  50:              ''' </summary>

  51:              RESOURCEDISPLAYTYPE_SERVER = 2

  52:              ''' <summary>

  53:              ''' 共享資源。

  54:              ''' </summary>

  55:              RESOURCEDISPLAYTYPE_SHARE = 3

  56:              ''' <summary>

  57:              ''' 檔案資源。

  58:              ''' </summary>

  59:              RESOURCEDISPLAYTYPE_FILE = 4

  60:              RESOURCEDISPLAYTYPE_GROUP = 5

  61:              RESOURCEDISPLAYTYPE_NETWORK = 6

  62:              RESOURCEDISPLAYTYPE_ROOT = 7

  63:              RESOURCEDISPLAYTYPE_SHAREADMIN = 8

  64:              RESOURCEDISPLAYTYPE_DIRECTORY = 9

  65:              RESOURCEDISPLAYTYPE_TREE = 10

  66:              RESOURCEDISPLAYTYPE_NDSCONTAINER = 11

  67:          End Enum

68:

  69:          Public Enum EResourceUsage As Integer

  70:              RESOURCEUSAGE_CONNECTABLE = &H1

  71:              RESOURCEUSAGE_CONTAINER = &H2

  72:              RESOURCEUSAGE_NOLOCALDEVICE = &H4

  73:              RESOURCEUSAGE_SIBLING = &H8

  74:              RESOURCEUSAGE_ATTACHED = &H10

  75:              RESOURCEUSAGE_ALL = (RESOURCEUSAGE_CONNECTABLE Or RESOURCEUSAGE_CONTAINER Or RESOURCEUSAGE_ATTACHED)

  76:              RESOURCEUSAGE_RESERVED = &H80000000

  77:          End Enum

78:

  79:          ''' <summary>

  80:          ''' 網路資源定義。

  81:          ''' </summary>

  82:          <StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Auto)> _

  83:          Public Class TNetResource

  84:              Public dwScope As EResourceScope

  85:              Public dwType As EResourceType

  86:              Public dwDisplayType As EResourceDisplayType

  87:              Public dwUsage As EResourceUsage

  88:              <MarshalAs(UnmanagedType.LPTStr)> _

  89:              Public LocalName As String

  90:              <MarshalAs(UnmanagedType.LPTStr)> _

  91:              Public RemoteName As String

  92:              <MarshalAs(UnmanagedType.LPTStr)> _

  93:              Public Comment As String

  94:              <MarshalAs(UnmanagedType.LPTStr)> _

  95:              Public Provider As String

  96:          End Class

97:

  98:          ''' <summary>

  99:          ''' 列舉網路芳鄰的網路資源。

 100:          ''' </summary>

 101:          ''' <param name="Handle">從 WNetOpenEnum 函數返回的一個控制碼。</param>

 102:          ''' <param name="Count">最初設為要枚舉的最大資源數量；或設為-1，表示枚舉盡可能多的資源。一旦返回，就會設為實際枚舉的資源數量。</param>

 103:          ''' <param name="NetResource">通常是一個位元組緩衝區的首位元組。該緩衝區裝載了列舉資訊。</param>

 104:          ''' <param name="Size">緩衝區大小。</param>

 105:          <DllImport("mpr.dll", CharSet:=CharSet.Auto)> _

 106:  Public Shared Function WNetEnumResource(ByVal Handle As IntPtr, ByRef Count As Integer, ByVal NetResource As IntPtr, ByRef Size As Integer) As Integer

 107:          End Function

 108:

 109:          ''' <summary>

 110:          ''' 啟動對網路資源進行列舉的過程。這個函數會返回由 WNetEnumResource 函數用於列舉資源所用的一個控制碼。

 111:          ''' </summary>

 112:          ''' <param name="Scope">要列舉的資源範圍。</param>

 113:          ''' <param name="Type">要列舉的資源類型。</param>

 114:          ''' <param name="Usage">要列舉的資源使用狀況。</param>

 115:          ''' <param name="NetResource">網路資源定義。</param>

 116:          ''' <param name="Handle">傳出一個控制碼。該控制碼由 WNetEnumResource 函數使用。必須用 WNetCloseEnum 函數將其清除。</param>

 117:          <DllImport("mpr.dll", CharSet:=CharSet.Auto)> _

 118:          Public Shared Function WNetOpenEnum(ByVal Scope As EResourceScope, ByVal Type As EResourceType, ByVal Usage As EResourceUsage, ByVal NetResource As TNetResource, <Out()> ByRef Handle As IntPtr) As Integer

 119:          End Function

 120:

 121:          ''' <summary>

 122:          ''' 結束列舉操作。

 123:          ''' </summary>

 124:          ''' <param name="Handle">由 WNetOpenEnum 函數返回的一個列舉控制碼。</param>

 125:          <DllImport("mpr.dll", CharSet:=CharSet.Auto)> _

 126:          Public Shared Function WNetCloseEnum(ByVal Handle As IntPtr) As Integer

 127:          End Function

 128:

 129:      End Class

下列程式碼中的 NetEnumResource 為列舉網路芳鄰的網路資源的函式，NetEnumResourceCallback 為執行 NetEnumResource 方法的回呼函式。

   1:          ''' <summary>

   2:          ''' 執行 NetEnumResource 方法的回呼函式。

   3:          ''' </summary>

   4:          ''' <param name="NetResource">網路資源定義。</param>

   5:          ''' <param name="Cancel">是否取消列舉動作。</param>

   6:          Public Delegate Sub NetEnumResourceCallback(ByVal NetResource As TAPIMpr.TNetResource, ByRef Cancel As Boolean)

7:

   8:          ''' <summary>

   9:          ''' 列舉網路芳鄰的網路資源。

  10:          ''' </summary>

  11:          ''' <param name="NetResource">網路資源定義。</param>

  12:          ''' <param name="CallBack">列舉過程中的回呼函式。</param>

  13:          Public Shared Sub NetEnumResource(ByVal NetResource As TAPIMpr.TNetResource, ByVal CallBack As NetEnumResourceCallback)

  14:              Dim bCancel As Boolean

  15:              Dim iRet As Integer

  16:              Dim oHandle As IntPtr = New IntPtr()

  17:              Dim iEntries As Integer

  18:              Dim iBuffer As Integer = 16384

  19:              Dim oBuffer As IntPtr

  20:              Dim oNetResource As TAPIMpr.TNetResource

  21:              Dim iPtr As Int32

  22:              Dim N1 As Integer

  23:              Dim oStructure As Object

24:

  25:              bCancel = False

  26:              Try

  27:                  iRet = TAPIMpr.WNetOpenEnum( _

  28:                      TAPIMpr.EResourceScope.RESOURCE_GLOBALNET, _

  29:                      TAPIMpr.EResourceType.RESOURCETYPE_ANY, _

  30:                      TAPIMpr.EResourceUsage.RESOURCEUSAGE_ALL, NetResource, oHandle)

  31:                  If iRet <> 0 Then Exit Sub

32:

  33:                  oBuffer = Marshal.AllocHGlobal(iBuffer)

  34:                  Do

  35:                      iEntries = -1

  36:                      iBuffer = 16384

  37:                      iRet = TAPIMpr.WNetEnumResource(oHandle, iEntries, oBuffer, iBuffer)

  38:                      If iRet <> 0 OrElse iEntries < 1 Then Exit Sub

  39:                      iPtr = oBuffer.ToInt32

  40:                      For N1 = 0 To iEntries - 1

  41:                          oStructure = Marshal.PtrToStructure(CType(iPtr, IntPtr), GetType(TAPIMpr.TNetResource))

  42:                          oNetResource = DirectCast(oStructure, TAPIMpr.TNetResource)

43:

  44:                          '列舉過程中的回呼函式

  45:                          CallBack.Invoke(oNetResource, bCancel)

  46:                          If bCancel = True Then Exit Do

47:

  48:                          '若為 RESOURCEUSAGE_CONTAINER 則利用遞迴往下層列舉網路資源

  49:                          If (TAPIMpr.EResourceUsage.RESOURCEUSAGE_CONTAINER = _

  50:                             (oNetResource.dwUsage And TAPIMpr.EResourceUsage.RESOURCEUSAGE_CONTAINER)) Then

  51:                              NetEnumResource(oNetResource, CallBack)

  52:                          End If

  53:                          iPtr = iPtr + Marshal.SizeOf(oNetResource)

  54:                      Next

  55:                  Loop

56:

  57:                  Marshal.FreeHGlobal(oBuffer)

  58:                  TAPIMpr.WNetCloseEnum(oHandle)

  59:              Catch ex As Exception

  60:              End Try

  61:          End Sub

在表單上放置一個 ListBox 控制項來顯示列舉的網路資源，呼叫 NetEnumResource 函式來進行列舉，呼叫 NetEnumResource 函式的引數需傳入事先定義好的 NetEnumResourceCallback 回呼函式；當列舉的過程式，當找到網路資源時就會執行 NetEnumResourceCallback 函式，利用傳入的 NetResource 引數就可以依序列舉網路資源。

   1:      ''' <summary>

   2:      ''' 執行 WNetEnumResource 方法的回呼函式。

   3:      ''' </summary>

   4:      ''' <param name="NetResource">網路資源定義。</param>

   5:      ''' <param name="Cancel">是否取消列舉動作。</param>

   6:      Public Sub NetEnumResourceCallback(ByVal NetResource As TAPIMpr.TNetResource, ByRef Cancel As Boolean)

   7:          Dim sText As String

8:

   9:          sText = String.Format(" {0} : LocalName='{1}' RemoteName='{2}'", NetResource.dwDisplayType.ToString, NetResource.LocalName, NetResource.RemoteName)

  10:          ListBox1.Items.Add(sText)

  11:          Application.DoEvents()

  12:      End Sub

13:

  14:      Private Sub Button10_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button10.Click

  15:          Me.Cursor = Cursors.WaitCursor

  16:          Try

  17:              ListBox1.Items.Clear()

  18:              TBMpr.NetEnumResource(Nothing, New NetEnumResourceCallback(AddressOf NetEnumResourceCallback))

  19:              MsgBox("執行完成!")

  20:          Finally

  21:              Me.Cursor = Cursors.Default

  22:          End Try

  23:      End Sub