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VB - Webcam in PictureBox anzeigen

Veröffentlicht von am 28.03.2010
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Diese Klasse erzeugt einen "Schnappschuss", sollte eine Web-Cam an den Computer angeschlossen und erkannt sein. In diesem Fall wird durch einen Button das Bild in einer PictureBox angezeigt.
Class ShowWebcam
    Dim videoHandle As IntPtr
    Declare Auto Function SendMessage Lib "user32" (ByVal hwnd As IntPtr, ByVal wMsg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer
    Declare Auto Function capCreateCaptureWindow Lib "avicap32.dll" (ByVal lpszWindowName As String, ByVal dwStyle As Integer, ByVal x As Short, ByVal y As Integer, ByVal nWidth As Short, ByVal nHeight As Short, ByVal hWndParent As IntPtr, ByVal nID As Byte) As IntPtr

    Const EM_LINEFROMCHAR As Integer = &HC9
    Const EM_LINEINDEX As Integer = &HBB

    Const WS_CHILD As Integer = &H40000000
    Const WS_VISIBLE As Integer = &H10000000

    Const WM_USER As Short = &H400S
    Const WM_CAP_START As Short = &H400S
    Const WM_CAP_EDIT_COPY As Short = WM_CAP_START + 30
    Const WM_CAP_DRIVER_CONNECT As Short = WM_CAP_START + 10
    Const WM_CAP_SET_PREVIEWRATE As Short = WM_CAP_START + 52
    Const WM_CAP_SET_OVERLAY As Short = WM_CAP_START + 51
    Const WM_CAP_SET_PREVIEW As Short = WM_CAP_START + 50
    Const WM_CAP_DRIVER_DISCONNECT As Short = WM_CAP_START + 11

    Function CreateCaptureWindow(ByRef hWndParent As IntPtr, Optional ByRef x As Short = 0, Optional ByRef y As Short = 0, Optional ByRef nWidth As Short = 640, Optional ByRef nHeight As Short = 420, Optional ByRef nCameraID As Integer = 0) As IntPtr
        Dim previewHandle As IntPtr

        previewHandle = capCreateCaptureWindow("Video", WS_CHILD + WS_VISIBLE, x, y, nWidth, nHeight, hWndParent, 1)
        SendMessage(previewHandle, WM_CAP_DRIVER_CONNECT, nCameraID, 0)
        SendMessage(previewHandle, WM_CAP_SET_PREVIEWRATE, 30, 0)
        SendMessage(previewHandle, WM_CAP_SET_OVERLAY, 1, 0)
        SendMessage(previewHandle, WM_CAP_SET_PREVIEW, 1, 0)

        Return previewHandle
    End Function

    Sub Disconnect(ByRef nCaptureHandle As IntPtr, Optional ByRef nCameraID As Integer = 0)
        SendMessage(nCaptureHandle, WM_CAP_DRIVER_DISCONNECT, nCameraID, 0)
    End Sub

    Sub Form1_FormClosing() Handles Me.FormClosing
        Me.Disconnect(videoHandle)
    End Sub

    Sub Button1_Click() Handles Button1.Click
        videoHandle = Me.CreateCaptureWindow(PictureBox1.Handle)
    End Sub
End Class

1 Kommentare zum Snippet

signItUp schrieb am 09.05.2011:
Hy,
ich habe das Beispiel probiert und mit einer Kamera funktioniert es auch problemlos.
Nur zwei Kameras konnte ich dann nicht mehr gleichzeitig in zwei verschiedenen PictureBoxen anzeigen.
Habt ihr hierzu einen Tipp?
 

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