Как получить доступ к веб-камере и сделать снимок

    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
    Public Const WM_CAP_GET_STATUS As Integer = WM_CAP + 54
    Public Const WM_CAP_DLG_VIDEOFORMAT As Integer = WM_CAP + 41
 
    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
    Dim hHwnd As Integer
 
    Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
        (ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Integer, _
        ByRef lParam As CAPSTATUS) As Boolean
 
    Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
     (ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Boolean, _
     ByRef lParam As Integer) As Boolean
 
    Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
         (ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Integer, _
         ByRef lParam As Integer) As Boolean
 
    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
 
    Structure POINTAPI
        Dim x As Integer
        Dim y As Integer
    End Structure
 
    Public Structure CAPSTATUS
        Dim uiImageWidth As Integer
        Dim uiImageHeight As Integer
        Dim fLiveWindow As Integer
        Dim fOverlayWindow As Integer
        Dim fScale As Integer
        Dim ptScroll As POINTAPI
        Dim fUsingDefaultPalette As Integer
        Dim fAudioHardware As Integer
        Dim fCapFileExists As Integer
        Dim dwCurrentVideoFrame As Integer
        Dim dwCurrentVideoFramesDropped As Integer
        Dim dwCurrentWaveSamples As Integer
        Dim dwCurrentTimeElapsedMS As Integer
        Dim hPalCurrent As Integer
        Dim fCapturingNow As Integer
        Dim dwReturn As Integer
        Dim wNumVideoAllocated As Integer
        Dim wNumAudioAllocated As Integer
    End Structure
 
    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_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
        If Button2.Enabled Then
            ClosePreviewWindow()
        End If
    End Sub
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        LoadDeviceList()
        If ListBox1.Items.Count > 0 Then
            Button1.Enabled = True
            ListBox1.SelectedIndex = 0
            Button1.Enabled = True
        Else
            ListBox1.Items.Add("No Capture Device")
            Button1.Enabled = False
        End If
        Me.AutoScrollMinSize = New Size(100, 100)
        Button2.Enabled = False
        Button3.Enabled = False
        PictureBox1.SizeMode = PictureBoxSizeMode.StretchImage
        If Button2.Enabled = False Then
            PictureBox1.Hide()
            Me.Width = 621
            Me.Height = 141
        End If
    End Sub
    Private Sub LoadDeviceList()
        Dim strName As String = Space(100)
        Dim strVer As String = Space(100)
        Dim bReturn As Boolean
        Dim x As Short = 0
        Do
            bReturn = capGetDriverDescriptionA(x, strName, 100, strVer, 100)
            If bReturn Then ListBox1.Items.Add(strName.Trim)
            x += CType(1, Short)
        Loop Until bReturn = False
    End Sub
 
    Private Sub OpenPreviewWindow()
        Dim iHeight As Integer = PictureBox1.Height
        Dim iWidth As Integer = PictureBox1.Width
        hHwnd = capCreateCaptureWindowA(iDevice.ToString, WS_VISIBLE Or WS_CHILD, 0, 0, 1280, _
            1024, PictureBox1.Handle.ToInt32, 0)
        If SendMessage(hHwnd, WM_CAP_DRIVER_CONNECT, iDevice, 0) Then
            SendMessage(hHwnd, WM_CAP_SET_SCALE, True, 0)
            SendMessage(hHwnd, WM_CAP_SET_PREVIEWRATE, 66, 0)
            SendMessage(hHwnd, WM_CAP_SET_PREVIEW, True, 0)
            SetWindowPos(hHwnd, HWND_BOTTOM, 0, 0, PictureBox1.Width, PictureBox1.Height, _
                    SWP_NOMOVE Or SWP_NOZORDER)
            Button3.Enabled = True
            Button2.Enabled = True
            Button1.Enabled = True
        Else
            DestroyWindow(hHwnd)
            Button3.Enabled = False
        End If
    End Sub
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        'Dim r As Rectangle
        iDevice = ListBox1.SelectedIndex
        OpenPreviewWindow()
        Dim s As CAPSTATUS
        ListBox1.Items.Add(String.Format("Video Size {0} x {1}", s.uiImageWidth, s.uiImageHeight))
        Me.Width = 640
        Me.Height = 700
        PictureBox1.Show()
    End Sub
 
    Private Sub ClosePreviewWindow()
        SendMessage(hHwnd, WM_CAP_DRIVER_DISCONNECT, iDevice, 0)
        DestroyWindow(hHwnd)
    End Sub
 
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        ClosePreviewWindow()
        Button3.Enabled = False
        Button2.Enabled = False
    End Sub
 
    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        Dim data As IDataObject
        Dim bmap As Bitmap
        SendMessage(hHwnd, WM_CAP_EDIT_COPY, 0, 0)
        data = Clipboard.GetDataObject()
        If data.GetDataPresent(GetType(System.Drawing.Bitmap)) Then
            bmap = CType(data.GetData(GetType(System.Drawing.Bitmap)), Bitmap)
            PictureBox1.Image = bmap
            Dim sfdImage = New SaveFileDialog
            Trace.Assert(Not (bmap Is Nothing))
            If sfdImage.ShowDialog = DialogResult.OK Then
                bmap.Save(sfdImage.FileName, Imaging.ImageFormat.Bmp)
            End If
        End If
    End Sub
 
End Class