Auto Detection / Notification of Inserted Media (CD)

Category:

C#, VB.NET, ASP.NET

Type:

Modules

Difficulty:

Intermediate

Author:

Anonymous

Version Compatibility: Visual Basic.NET

More information:

This code shows how we can intercept windows form messages to detect the insertion or removal of a CD. Along with System.Windows.Forms.Message, this project uses System.Runtime.InteropServices to implement this functionality. Be sure to add a listBox control to your form before running the application.

Instructions: Copy the declarations and code below and paste directly into your VB project.

Declarations:
Private Const DBTF_MEDIA As UInteger = &H1 ' media comings and goings Private Const DBT_DEVICEARRIVAL As UInteger = &H8000 ' system detected a new device Private Const DBT_DEVICEREMOVECOMPLETE As UInteger = &H8004 ' device is gone Private Const DBT_DEVTYP_VOLUME As UInteger = &H2 ' logical volume Private Structure DEV_BROADCAST_HDR Public dbch_size As Int32 Public dbch_devicetype As Int32 Public dbch_reserved As Int32 End Structure Private Structure DEV_BROADCAST_VOLUME Public dbcv_size As Int32 Public dbcv_devicetype As Int32 Public dbcv_reserved As Int32 Public dbcv_unitmask As Int32 Public dbcv_flags As Int16 End Structure

Code:

Protected Function FirstDriveFromMask(ByVal Unit As Int32) As Char
        Dim Ix As Integer
        For Ix = 0 To 25
            If Unit And Ix Then Exit For
            Unit = Unit >> 1
        Next
        Return Chr(Ix + Asc("A"))
    End Function

Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
        Select Case m.WParam.ToInt32
            Case DBT_DEVICEARRIVAL
                Dim b As DEV_BROADCAST_HDR
                b = System.Runtime.InteropServices.Marshal.PtrToStructure(m.LParam, GetType(DEV_BROADCAST_HDR))
                If b.dbch_devicetype = DBT_DEVTYP_VOLUME Then
                    Dim c As DEV_BROADCAST_VOLUME
                    c = System.Runtime.InteropServices.Marshal.PtrToStructure(m.LParam, GetType(DEV_BROADCAST_VOLUME))
                    If c.dbcv_flags And DBTF_MEDIA Then
                        ListBox1.Items.Add("Drive " + FirstDriveFromMask(c.dbcv_unitmask) + ": arrived")
                    End If
                End If
            Case DBT_DEVICEREMOVECOMPLETE
                Dim b As DEV_BROADCAST_HDR
                b = System.Runtime.InteropServices.Marshal.PtrToStructure(m.LParam, GetType(DEV_BROADCAST_HDR))
                If b.dbch_devicetype = DBT_DEVTYP_VOLUME Then
                    Dim c As DEV_BROADCAST_VOLUME
                    c = System.Runtime.InteropServices.Marshal.PtrToStructure(m.LParam, GetType(DEV_BROADCAST_VOLUME))
                    If c.dbcv_flags And DBTF_MEDIA Then
                        ListBox1.Items.Add("Drive " + FirstDriveFromMask(c.dbcv_unitmask) + ": goes")
                    End If
                End If
        End Select
        MyBase.WndProc(m)
    End Sub