vb.net与usb VBNET

vb.net 读取扫描枪USB接口数据的实例

USB比较难抓数据，建议是USB模拟串口，或者直接就是串口，这样数据比较好抓。

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USB上传模式是鼠标光标在哪数据就上传在哪，所以你抓USB的数据的很难！

X猫-思刊办公专营店

VB.NET 有4个TEXTBOX，4个扫码枪,怎么在指定TEXTBOX对应到指定的扫码枪

如果是usb扫描枪，是焦点在哪它就输入在哪，不能自动对应到相应的文本框

如果是串口扫描枪可以实现你的功能，在代码里判断相应的串口对应文本框

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检测插入U盘时执行某段代码，并能获取U盘盘符

以下内容为网络提供,但我自己验证可行,供你参考.

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

ComboBox1.Items.Clear()

Dim s() As DriveInfo = DriveInfo.GetDrives

For Each drive As DriveInfo In s

If drive.DriveType = DriveType.Removable Then

ListBox1.Items.Add("U盘已插入！盘符为:" + drive.Name.ToString())

ComboBox1.Items.Add(drive.Name)

End If

Next

BtnWrite.Enabled = True

BtnRead.Enabled = True

Case DBT_CONFIGCHANGECANCELED

Case DBT_CONFIGCHANGED

Case DBT_CUSTOMEVENT

Case DBT_DEVICEQUERYREMOVE

Case DBT_DEVICEQUERYREMOVEFAILED

Case DBT_DEVICEREMOVECOMPLETE 'U盘卸载

ListBox1.Items.Add("U盘卸载！")

BtnWrite.Enabled = False

BtnRead.Enabled = False

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

ListBox1.Items.Add("请您现在插入U盘至USB接口！")

End Sub

Private Sub BtnWrite_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnWrite.Click

If ComboBox1.Text = "" Then

MsgBox("请选择U盘盘符！", MsgBoxStyle.Exclamation, "Warn")

Else

Dim Writer As StreamWriter = Nothing

Try

Dim fileName As String = ComboBox1.Text + "Test.txt"

Writer = New StreamWriter(fileName)

Writer.WriteLine(InputBox("老四，请输入要保存的字符串", "输入信息", "Input then Test String! hehe!"))

MsgBox("Write to " + fileName + " Success!")

Catch ex As Exception

MsgBox(ex.Message, MsgBoxStyle.Critical, "Write 失败")

Finally

If Writer IsNot Nothing Then Writer.Close()

End Try

End If

End Sub

Private Sub BtnRead_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnRead.Click

If ComboBox1.Text = "" Then

MsgBox("请选择U盘盘符！", MsgBoxStyle.Exclamation, "Warn")

Else

Dim Reader As StreamReader = Nothing

Try

Dim fileName As String = ComboBox1.Text + "Test.txt"

Reader = New StreamReader(fileName)

MsgBox("Read from " + fileName + vbCrLf + Reader.ReadToEnd, MsgBoxStyle.Information, "Info")

Catch ex As Exception

MsgBox(ex.Message, MsgBoxStyle.Critical, "Read 失败")

Finally

If Reader IsNot Nothing Then Reader.Close()

End Try

End If

End Sub

End Class