directshow-如何检测网络摄像头的插拔?
DirectShow是否有一种简单的方法来检测网络摄像头是否已插入(USB)或是否有人已拔下(然后轮询或搜索) <>我见过微软媒体基金会的代码,但它很复杂,媒体基础不可安装在directshow-如何检测网络摄像头的插拔?,directshow,directshow.net,Directshow,Directshow.net,DirectShow是否有一种简单的方法来检测网络摄像头是否已插入(USB)或是否有人已拔下(然后轮询或搜索) 我见过微软媒体基金会的代码,但它很复杂,媒体基础不可安装在
Dim CamEventWatcher As ManagementEventWatcher
Public Delegate Sub SetMessageCallback(ByVal [_Msg] As Boolean)
Private Sub MessageCallback(ByVal _Msg As Boolean)
If (_Msg) Then
'cam connected
Else
'camera removed
End If
End Sub
Private Sub RemoveCameraUSBHandler()
Try
If Not CamEventWatcher Is Nothing Then
CamEventWatcher.Stop()
End If
Catch ex As Exception
End Try
End Sub
Private Sub AddCameraUSBHandler()
Dim q As WqlEventQuery
Dim scope As ManagementScope = New ManagementScope("root\CIMV2")
scope.Options.EnablePrivileges = True
Try
q = New WqlEventQuery()
q.EventClassName = "__InstanceOperationEvent"
q.WithinInterval = New TimeSpan(0, 0, 1)
q.Condition = "TargetInstance ISA 'Win32_USBControllerdevice'"
CamEventWatcher = New ManagementEventWatcher(scope, q)
AddHandler CamEventWatcher.EventArrived, AddressOf CamUSBEvent
CamEventWatcher.Start()
Catch ex As Exception
End Try
End Sub
Private iCreatedFired As Integer = 0
Private iRemovedFired As Integer = 0
Public Sub CamUSBEvent(ByVal sender As System.Object, ByVal e As EventArrivedEventArgs)
If e.NewEvent.ClassPath.ClassName = "__InstanceCreationEvent" Then
Dim sAntecedent As String
Dim sDependent As String
sAntecedent = e.NewEvent.Properties("TargetInstance").Value.Properties("Antecedent").Value.ToString() + ControlChars.CrLf
sDependent = e.NewEvent.Properties("TargetInstance").Value.Properties("Dependent").Value.ToString() + ControlChars.CrLf
If sDependent.Contains(CAM_DEV_ID) Then
iCreatedFired += 1
If (iCreatedFired = 1) Then
e.NewEvent.Dispose()
Return
End If
iCreatedFired = 0
iRemovedFired = 0
Dim _delegate As New SetMessageCallback(AddressOf MessageCallback)
Me.Invoke(_delegate, New Object() {True})
End If
ElseIf e.NewEvent.ClassPath.ClassName = "__InstanceDeletionEvent" Then
Dim sAntecedent As String
Dim sDependent As String
sAntecedent = e.NewEvent.Properties("TargetInstance").Value.Properties("Antecedent").Value.ToString() + ControlChars.CrLf
sDependent = e.NewEvent.Properties("TargetInstance").Value.Properties("Dependent").Value.ToString() + ControlChars.CrLf
If sDependent.Contains(CAM_DEV_ID) Then
iRemovedFired += 1
If (iRemovedFired = 1) Then
e.NewEvent.Dispose()
Return
End If
iCreatedFired = 0
iRemovedFired = 0
Dim _delegate As New SetMessageCallback(AddressOf MessageCallback)
Me.Invoke(_delegate, New Object() {False})
End If
End If
e.NewEvent.Dispose()
End Sub
请注意,这可能有点草率,我不得不删除一些我不想看到的代码,虽然这个例程可以做到,但我从来没有见过这种功能在DS中可用或实现。。。。