一个驱动webcam的类，利用通用的摄像头驱动程序avicap32.dll

Imports System.Runtime.InteropServices

Public Class Form1
Inherits System.Windows.Forms.Form

#Region " Windows Form Designer generated code "

Public Sub New()
  MyBase.New()

'This call is required by the Windows Form Designer.
  InitializeComponent()

'Add any initialization after the InitializeComponent() call

End Sub

'Form overrides dispose to clean up the component list.
Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
  If disposing Then
   If Not (components Is Nothing) Then
components.Dispose()
   End If
  End If
  MyBase.Dispose(disposing)
End Sub

'Required by the Windows Form Designer
Private components As System.ComponentModel.IContainer

'NOTE: The following procedure is required by the Windows Form Designer
'It can be modified using the Windows Form Designer. 
'Do not modify it using the code editor.
Friend WithEvents picCapture As System.Windows.Forms.PictureBox
Friend WithEvents lstDevices As System.Windows.Forms.ListBox
Friend WithEvents lblDevice As System.Windows.Forms.Label
Friend WithEvents btnStart As System.Windows.Forms.Button
Friend WithEvents btnSave As System.Windows.Forms.Button
Friend WithEvents btnStop As System.Windows.Forms.Button
Friend WithEvents sfdImage As System.Windows.Forms.SaveFileDialog
<System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
  Me.picCapture = New System.Windows.Forms.PictureBox()
  Me.lstDevices = New System.Windows.Forms.ListBox()
  Me.lblDevice = New System.Windows.Forms.Label()
  Me.btnStart = New System.Windows.Forms.Button()
  Me.btnSave = New System.Windows.Forms.Button()
  Me.btnStop = New System.Windows.Forms.Button()
  Me.sfdImage = New System.Windows.Forms.SaveFileDialog()
  Me.SuspendLayout()
  '
  'picCapture
  '
  Me.picCapture.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D
  Me.picCapture.Location = New System.Drawing.Point(208, 24)
  Me.picCapture.Name = "picCapture"
  Me.picCapture.Size = New System.Drawing.Size(256, 272)
  Me.picCapture.TabIndex = 0
  Me.picCapture.TabStop = False
  '
  'lstDevices
  '
  Me.lstDevices.Location = New System.Drawing.Point(8, 55)
  Me.lstDevices.Name = "lstDevices"
  Me.lstDevices.Size = New System.Drawing.Size(184, 238)
  Me.lstDevices.TabIndex = 1
  '
  'lblDevice
  '
  Me.lblDevice.Location = New System.Drawing.Point(8, 32)
  Me.lblDevice.Name = "lblDevice"
  Me.lblDevice.Size = New System.Drawing.Size(184, 16)
  Me.lblDevice.TabIndex = 2
  Me.lblDevice.Text = "Available Devices"
  Me.lblDevice.TextAlign = System.Drawing.ContentAlignment.TopCenter
  '
  'btnStart
  '
  Me.btnStart.Location = New System.Drawing.Point(20, 320)
  Me.btnStart.Name = "btnStart"
  Me.btnStart.Size = New System.Drawing.Size(112, 32)
  Me.btnStart.TabIndex = 3
  Me.btnStart.Text = "Start Preview"
  '
  'btnSave
  '
  Me.btnSave.Anchor = (System.Windows.Forms.AnchorStyles.Bottom Or System.Windows.Forms.AnchorStyles.Right)
  Me.btnSave.Location = New System.Drawing.Point(348, 320)
  Me.btnSave.Name = "btnSave"
  Me.btnSave.Size = New System.Drawing.Size(112, 32)
  Me.btnSave.TabIndex = 4
  Me.btnSave.Text = "Save Image"
  '
  'btnStop
  '
  Me.btnStop.Location = New System.Drawing.Point(184, 320)
  Me.btnStop.Name = "btnStop"
  Me.btnStop.Size = New System.Drawing.Size(112, 32)
  Me.btnStop.TabIndex = 5
  Me.btnStop.Text = "Stop Preview"
  '
  'sfdImage
  '
  Me.sfdImage.FileName = "Webcam1"
  Me.sfdImage.Filter = "Bitmap|*.bmp"
  '
  'Form1
  '
  Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
  Me.ClientSize = New System.Drawing.Size(480, 382)
  Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.btnStop, Me.btnSave, Me.btnStart, Me.lblDevice, Me.lstDevices, Me.picCapture})
  Me.Name = "Form1"
  Me.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen
  Me.Text = "Video Capture"
  Me.ResumeLayout(False)

End Sub

#End Region

Const WM_CAP As Short = &H400S

Const WM_CAP_DRIVER_CONNECT As Integer = WM_CAP + 10
Const WM_CAP_DRIVER_DISCONNECT As Integer = WM_CAP + 11
Const WM_CAP_EDIT_COPY As Integer = WM_CAP + 30

Const WM_CAP_SET_PREVIEW As Integer = WM_CAP + 50
Const WM_CAP_SET_PREVIEWRATE As Integer = WM_CAP + 52
Const WM_CAP_SET_SCALE As Integer = WM_CAP + 53
Const WS_CHILD As Integer = &H40000000
Const WS_VISIBLE As Integer = &H10000000
Const SWP_NOMOVE As Short = &H2S
Const SWP_NOSIZE As Short = 1
Const SWP_NOZORDER As Short = &H4S
Const HWND_BOTTOM As Short = 1

Dim iDevice As Integer = 0 ' Current device ID
Dim hHwnd As Integer ' Handle to preview window

Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
  (ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Integer, _
  <MarshalAs(UnmanagedType.AsAny)> ByVal lParam As Object) As Integer

Declare Function SetWindowPos Lib "user32" Alias "SetWindowPos" (ByVal hwnd As Integer, _
  ByVal hWndInsertAfter As Integer, ByVal x As Integer, ByVal y As Integer, _
  ByVal cx As Integer, ByVal cy As Integer, ByVal wFlags As Integer) As Integer

Declare Function DestroyWindow Lib "user32" (ByVal hndw As Integer) As Boolean

Declare Function capCreateCaptureWindowA Lib "avicap32.dll" _
  (ByVal lpszWindowName As String, ByVal dwStyle As Integer, _
  ByVal x As Integer, ByVal y As Integer, ByVal nWidth As Integer, _
  ByVal nHeight As Short, ByVal hWndParent As Integer, _
  ByVal nID As Integer) As Integer

Declare Function capGetDriverDescriptionA Lib "avicap32.dll" (ByVal wDriver As Short, _
  ByVal lpszName As String, ByVal cbName As Integer, ByVal lpszVer As String, _
  ByVal cbVer As Integer) As Boolean

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
  LoadDeviceList()
  If lstDevices.Items.Count > 0 Then
   btnStart.Enabled = True
   lstDevices.SelectedIndex = 0
   btnStart.Enabled = True
  Else
   lstDevices.Items.Add("No Capture Device")
   btnStart.Enabled = False
  End If

btnStop.Enabled = False
  btnSave.Enabled = False
  picCapture.SizeMode = PictureBoxSizeMode.StretchImage
End Sub

Private Sub LoadDeviceList()
  Dim strName As String = Space(100)
  Dim strVer As String = Space(100)
  Dim bReturn As Boolean
  Dim x As Integer = 0

'
  ' Load name of all avialable devices into the lstDevices
  '

Do
   '
   '   Get Driver name and version
   '
   bReturn = capGetDriverDescriptionA(x, strName, 100, strVer, 100)

'
   ' If there was a device add device name to the list
   '
   If bReturn Then lstDevices.Items.Add(strName.Trim)
   x += 1
  Loop Until bReturn = False
End Sub

Private Sub OpenPreviewWindow()
  Dim iHeight As Integer = picCapture.Height
  Dim iWidth As Integer = picCapture.Width

'
  ' Open Preview window in picturebox
  '
  hHwnd = capCreateCaptureWindowA(iDevice, WS_VISIBLE Or WS_CHILD, 0, 0, 640, _
   480, picCapture.Handle.ToInt32, 0)

'
  ' Connect to device
  '
  If SendMessage(hHwnd, WM_CAP_DRIVER_CONNECT, iDevice, 0) Then
   '
   'Set the preview scale
   '
   SendMessage(hHwnd, WM_CAP_SET_SCALE, True, 0)

'
   'Set the preview rate in milliseconds
   '
   SendMessage(hHwnd, WM_CAP_SET_PREVIEWRATE, 66, 0)

'
   'Start previewing the image from the camera
   '
   SendMessage(hHwnd, WM_CAP_SET_PREVIEW, True, 0)

'
   ' Resize window to fit in picturebox
   '
   SetWindowPos(hHwnd, HWND_BOTTOM, 0, 0, picCapture.Width, picCapture.Height, _
  SWP_NOMOVE Or SWP_NOZORDER)

btnSave.Enabled = True
   btnStop.Enabled = True
   btnStart.Enabled = False
  Else
   '
   ' Error connecting to device close window
   '
   DestroyWindow(hHwnd)

btnSave.Enabled = False
  End If
End Sub

Private Sub btnStart_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStart.Click
  iDevice = lstDevices.SelectedIndex
  OpenPreviewWindow()
End Sub

Private Sub ClosePreviewWindow()
  '
  ' Disconnect from device
  '
  SendMessage(hHwnd, WM_CAP_DRIVER_DISCONNECT, iDevice, 0)

'
  ' close window
  '

DestroyWindow(hHwnd)
End Sub

Private Sub btnStop_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStop.Click
  ClosePreviewWindow()
  btnSave.Enabled = False
  btnStart.Enabled = True
  btnStop.Enabled = False
End Sub

Private Sub btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click
  Dim data As IDataObject
  Dim bmap As Image

'
  ' Copy image to clipboard
  '
  SendMessage(hHwnd, WM_CAP_EDIT_COPY, 0, 0)

'
  ' Get image from clipboard and convert it to a bitmap
  '
  data = Clipboard.GetDataObject()
  If data.GetDataPresent(GetType(System.Drawing.Bitmap)) Then
   bmap = CType(data.GetData(GetType(System.Drawing.Bitmap)), Image)
   picCapture.Image = bmap
   ClosePreviewWindow()
   btnSave.Enabled = False
   btnStop.Enabled = False
   btnStart.Enabled = True

If sfdImage.ShowDialog = DialogResult.OK Then
bmap.Save(sfdImage.FileName, Imaging.ImageFormat.Bmp)
   End If

End If
End Sub

Private Sub Form1_Closing(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles MyBase.Closing
  If btnStop.Enabled Then
   ClosePreviewWindow()
  End If
End Sub
End Class