请问这问题是什么意思？VB2010 WEBCAM问题

pikachew

   

Public Class Form1
    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
    Dim hHwnd As Integer
    Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Integer, 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 LoadDeviceList()
        Dim strName As String = Space(100)
        Dim strVer As String = Space(100)
        Dim bReturn As Boolean
        Dim x As Integer = 0
        Do
            bReturn = capGetDriverDescriptionA(x, strName, 100, strVer, 100)
            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
        hHwnd = capCreateCaptureWindowA(iDevice, WS_VISIBLE Or WS_CHILD, 0, 0, 640, 480, picCapture.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, picCapture.Width, picCapture.Height, SWP_NOMOVE Or SWP_NOZORDER)
            btnSave.Enabled = True
            btnStop.Enabled = True
            btnStart.Enabled = False
        Else
            DestroyWindow(hHwnd)
            btnSave.Enabled = False
        End If
    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
        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)), 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 ClosePreviewWindow()
        SendMessage(hHwnd, WM_CAP_DRIVER_DISCONNECT, iDevice, 0)
        DestroyWindow(hHwnd)
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        LoadDeviceList()
    End Sub

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

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


我是跟着他的CODING来做的
可是它的可以RUN，我的不可以。
”
A call to PInvoke function 'webcam!webcam.Form1::SendMessage' has unbalanced the stack. This is likely because the managed PInvoke signature does not match the unmanaged target signature. Check that the calling convention and parameters of the PInvoke signature match the target unmanaged signature.“

这是我得到的ERROR MESSAGE
    Private Sub OpenPreviewWindow()
        Dim iHeight As Integer = picCapture.Height
        Dim iWidth As Integer = picCapture.Width
        hHwnd = capCreateCaptureWindowA(iDevice, WS_VISIBLE Or WS_CHILD, 0, 0, 640, 480, picCapture.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, picCapture.Width, picCapture.Height, SWP_NOMOVE Or SWP_NOZORDER)
            btnSave.Enabled = True
            btnStop.Enabled = True
            btnStart.Enabled = False
        Else
            DestroyWindow(hHwnd)
            btnSave.Enabled = False
        End If
    End Sub
他是POINT TO 这条SEGMENT OF CODES 的
请问该如和解决呢？
谢谢

Super-Tomato

Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Integer, ByVal wMsg As Integer, ByVal wParam As Integer, ByVal lParam As Object) As Integer

我是跟着他的CODING来做的
可是它的可以RUN，我的不可以。
”
A call to PInvoke function 'webcam!webcam.Form1::SendMessage' has unbalanced the stack. This is likely because the managed PInvoke signature does not match the unmanaged target signature. Check that the calling convention and parameters of the PInvoke signature match the target unmanaged signature.“


pikachew 发表于 2011-9-1 12:35 PM

确認一下 SendMessage 所傳递的参數都正确不為空。

pikachew

回复 2# Super-Tomato


    你的意思是指CODING问题？
谢谢

Super-Tomato

回复  Super-Tomato


    你的意思是指CODING问题？
谢谢
pikachew 发表于 2011-9-1 11:30 PM

是不是 coding 問題要自己 trace 才知道，我没在用 VB 只能從你的 code 中猜测，而且 coding 最好严谨一點 hWnd 没先判断是否為 null 就使用的話，也許自己電腦上没事但别台電腦使用的話，也許就因為没過滤好而出現錯誤

pikachew

回复 4# Super-Tomato

噢噢
谢谢了
我再去试试看