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vb.net读usb的简单介绍

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vb.net编程接受U盘准备卸载用的windows消息 DBT_DEVICEQUERYREMOVE总是没反应，据说是因为默认注册的消息里在我的XP+VB2010环境下，测试U盘插入拔出，没有问题：
Private WM_DEVICECHANGE As Integer = H219
Public Enum WM_DEVICECHANGE_WPPARAMS As Integer
DBT_CONFIGCHANGECANCELED = H19
DBT_CONFIGCHANGED = H18
DBT_CUSTOMEVENT = H8006
DBT_DEVICEARRIVAL = H8000
DBT_DEVICEQUERYREMOVE = H8001
DBT_DEVICEQUERYREMOVEFAILED = H8002
DBT_DEVICEREMOVECOMPLETE = H8004
DBT_DEVICEREMOVEPENDING = H8003
DBT_DEVICETYPESPECIFIC = H8005
【vb.net读usb的简单介绍】DBT_DEVNODES_CHANGED = H7
DBT_QUERYCHANGECONFIG = H17
DBT_USERDEFINED = HFFFF
End Enum
Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
If m.Msg = WM_DEVICECHANGE Then
Select Case m.WParam
Case WM_DEVICECHANGE_WPPARAMS.DBT_DEVICEARRIVAL
MsgBox("USB device is just plugged in!")
Case WM_DEVICECHANGE_WPPARAMS.DBT_DEVICEREMOVECOMPLETE
MsgBox("USB device is just taken out")
End Select
End If
MyBase.WndProc(m)
End Sub
vb.net 如何判断u盘是否接入窗体上添加两个标签：Label1和Label2
下面代码经过VB 2005测试通过 。
Imports System.IO
Public Class Form1
Public Const WM_DEVICECHANGE = H219
Public Const DBT_DEVICEARRIVAL = H8000
Public Const DBT_CONFIGCHANGECANCELED = H19
Public Const DBT_CONFIGCHANGED = H18
Public Const DBT_CUSTOMEVENT = H8006
Public Const DBT_DEVICEQUERYREMOVE = H8001
Public Const DBT_DEVICEQUERYREMOVEFAILED = H8002
Public Const DBT_DEVICEREMOVECOMPLETE = H8004
Public Const DBT_DEVICEREMOVEPENDING = H8003
Public Const DBT_DEVICETYPESPECIFIC = H8005
Public Const DBT_DEVNODES_CHANGED = H7
Public Const DBT_QUERYCHANGECONFIG = H17
Public Const DBT_USERDEFINED = HFFFF
Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
If m.Msg = WM_DEVICECHANGE Then
Select Case m.WParam
Case WM_DEVICECHANGE
Case DBT_DEVICEARRIVAL 'U盘插入
Dim s() As DriveInfo = DriveInfo.GetDrives
For Each drive As DriveInfo In s
If drive.DriveType = DriveType.Removable Then
Label2.Text = "U盘已经插入！盘符为:" + drive.Name.ToString()
End If
Next
Case DBT_CONFIGCHANGECANCELED
Case DBT_CONFIGCHANGED
Case DBT_CUSTOMEVENT
Case DBT_DEVICEQUERYREMOVE
Case DBT_DEVICEQUERYREMOVEFAILED
Case DBT_DEVICEREMOVECOMPLETE 'U盘卸载
Label2.Text = "U盘已经拔出！"
Case DBT_DEVICEREMOVEPENDING
Case DBT_DEVICETYPESPECIFIC
Case DBT_DEVNODES_CHANGED
Case DBT_QUERYCHANGECONFIG
Case DBT_USERDEFINED
End Select
End If
MyBase.WndProc(m)
End Sub
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Label1.Text = "请操作U盘！"
Label2.Text = ""
End Sub
End Class
VB.NET怎样把USB摄像头在显示器上输出的实时画面（像素信息），引入到数据库.用directshow获取帧缓存,转换为标准图像格式(比如jpg,png这些),存储到数据库的image字段里就行了.
vb.net 二进制读取文件VB.NET打开二进制文件用fileopen完成 ， 打开二进制文件的形式为：openmode.binary
读取二进制文件用的是fileget方法，写入二进制文件用的是fileput方法 。
应用示例：将一批随机数保存在一个dat文件中，然后再将其提取到文本框中 。
二进制文件的读写一批随机数的存?。绦蛭?
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim x, i, fn As Integer
Dim s As String = ""
fn = FreeFile()
FileOpen(fn, "d:\data.dat", OpenMode.Binary)

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