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标题: 请问这问题是什么意思？VB2010 WEBCAM问题 [打印本页]

作者: pikachew 时间: 2011-9-1 12:35 PM
标题: 请问这问题是什么意思？VB2010 WEBCAM问题
[youtube]dMQNlrkGWQ[/youtube]
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

作者: Super-Tomato 时间: 2011-9-1 11:20 PM

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。

作者: pikachew 时间: 2011-9-1 11:30 PM
回复 2# Super-Tomato

你的意思是指CODING问题？
谢谢

作者: Super-Tomato 时间: 2011-9-1 11:35 PM

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

作者: pikachew 时间: 2011-9-1 11:41 PM
回复 4# Super-Tomato

噢噢
谢谢了
我再去试试看

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