Question

下面是我在vb留言板上看到的一些代码，但我不记得在哪里。它可能是vbforums.com。我做了一些代码更改，然后测试代码，让它抛出一个消息框，其中附加或删除了新的USB设备的驱动器号。它使用应用程序子类来拦截消息，并检查是否有可移动卷被删除，插入，附加等激活。如果是，那么它将解析设备的卷驱动器号并抛出一个消息框让你知道。应该可以检测到具有可移动磁盘卷的USB设备（如闪存驱动器（也称为Thumb Drive或Pen Drive）），外部硬盘驱动器等。我的测试认识到不同的usb卷没有问题。您可以在VB.NET，Visual Basic 2008，VB 2010,2013等中使用此代码来检查usb卷设备的到达和删除。您还可以进行一些更改以使其适用于VB 6.0。 Visual Basic 6.0将需要一个或两个附加API调用子类。

Answer 1

Protected Overrides Sub WndProc(ByRef M As System.Windows.Forms.Message)
    '
    'These are the required subclassing codes for detecting device based removal and arrival.
    '
    If M.Msg = WM_DEVICECHANGE Then

        Select Case M.WParam
            '
            'Check if a device was added.
            Case DBT_DEVICEARRIVAL

                Dim DevType As Integer = Runtime.InteropServices.Marshal.ReadInt32(M.LParam, 4)

                If DevType = DBT_DEVTYP_VOLUME Then

                    Dim Vol As New DEV_BROADCAST_VOLUME

                    Vol = Runtime.InteropServices.Marshal.PtrToStructure(M.LParam, GetType(DEV_BROADCAST_VOLUME))

                    If Vol.Dbcv_Flags = 0 Then

                        For i As Integer = 0 To 20

                            If Math.Pow(2, i) = Vol.Dbcv_Unitmask Then

                                Dim Usb As String = Chr(65 + i) + ":\"

                                MsgBox("Looks like a USB device was plugged in!" & vbNewLine & vbNewLine & "The drive letter is: " & Usb.ToString)

                                Exit For

                            End If

                        Next

                    End If

                End If
                '
                'Check if the message was for the removal of a device.
            Case DBT_DEVICEREMOVECOMPLETE

                Dim DevType As Integer = Runtime.InteropServices.Marshal.ReadInt32(M.LParam, 4)

                If DevType = DBT_DEVTYP_VOLUME Then

                    Dim Vol As New DEV_BROADCAST_VOLUME

                    Vol = Runtime.InteropServices.Marshal.PtrToStructure(M.LParam, GetType(DEV_BROADCAST_VOLUME))

                    If Vol.Dbcv_Flags = 0 Then

                        For i As Integer = 0 To 20

                            If Math.Pow(2, i) = Vol.Dbcv_Unitmask Then

                                Dim Usb As String = Chr(65 + i) + ":\"

                                MsgBox("Looks like a volume device was removed!" & vbNewLine & vbNewLine & "The drive letter is: " & Usb.ToString)

                                Exit For

                            End If

                        Next

                    End If

                End If

        End Select

    End If

    MyBase.WndProc(M)

End Sub

检测何时连接或移除可移动USB卷驱动器设备 - VB.NET

1 个答案: