واسه این کار چندین راه وجود داره.
یکی از این راه ها استفاده از توابع یه dll تو windows به نام avicap32.dll هست.
راه های دیگه و بهتر استفاده از توابع directx وdirectshow هست.
راه دیگه ای هم هست که البته مختص webcam هست و اون برنامه نویسی از روش wiaاست.
کد:
[align=left]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
picCapture.SizeMode = PictureBoxSizeMode.AutoSize
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, 640, 480, _
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, 640, 480)
'
' 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[/align]