How to control USB port in C#

[mustafa828]

Hello everybody

I'm developing application using visual C#, and also using Barcode reader connected to USB port, some time i need to stop the barcode reader from reading when the cursor will be in another TextBox, for example when it is inside the price TextBox i don't want it to work.
Please if you have any information it will be helpful to me.
thanks in advance to all of you.

[Frinavale]

The manufacturers of the Barcode Reader should provide you with the drivers necessary to control it.

To connect to a usb you should use the System.IO class...

For example, the following code snippet will connect to a USB key (thumb drive), read it's information and create a text file on the USB key containing the USB key's information.

Try
            'Making sure to demand permission to access USB
            Dim myPerm As New FileIOPermission(PermissionState.Unrestricted)
            myPerm.Demand()
 
            Dim ValidDriveLetters As String = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
            Dim info As System.IO.DriveInfo
            Dim sb As New StringBuilder
            Dim i As Integer
            Dim len As Integer = ValidDriveLetters.Length - 1
            For i = 0 To len
                info = New System.IO.DriveInfo(ValidDriveLetters(i))
                If info.IsReady Then
                    If String.Compare(info.VolumeLabel, "NameOfMyUsbKey", True) = 0 Then
                        sb.Append(info.DriveFormat)
                        Dim wr As IO.StreamWriter = IO.File.AppendText(info.Name + "test.txt")
                        wr.WriteLine("AvailableFreeSpace: " + info.AvailableFreeSpace.ToString)
                        wr.WriteLine("DriveFormat: " + info.DriveFormat)
                        wr.WriteLine("DriveType: " + info.DriveType.ToString)
                        wr.WriteLine("Name: " + info.Name)
                        wr.WriteLine("TotalFreeSpace: " + info.TotalFreeSpace.ToString)
                        wr.WriteLine("TotalSize: " + info.TotalSize.ToString)
                        wr.WriteLine("VolumeLabel: " + info.VolumeLabel)
                        wr.Flush()
                        wr.Close()
                    End If
                End If
            Next
        Catch ex As Exception
            LBL_Error.Text = "Failed to get permissions: " + ex.Message + " " + ex.StackTrace
        End Try

I doubt you are going to access your reader in this manner.
You're going to have to use the drivers to control your Barcode reader...contact the manufacturer for any software development kits available.

-Frinny

[mustafa828]

Thank you Frinavale for your replay.

The barcode reader is working properly like a keyboard without any driver software, immediatly after i connected to the computer, i need only to stop it from working through my application using VC#.

The manufactory didn't give me any details about this.
from this website you can see the barcode reader which i purchased.

http://www.svbinternational.com/bar_code_scanners/bar_code_scannerusb.htm

model: SVB-0006

[nmsreddi]

Hello

I dint get your question properly,

when ever you are reading a barcode then the details related to that will be retrived from the existing database, when you are using the barcode for your purpose why you need to enter text again .can you give some more clarification about your application.

Thank you Frinavale for your replay.

The barcode reader is working properly like a keyboard without any driver software, immediatly after i connected to the computer, i need only to stop it from working through my application using VC#.

The manufactory didn't give me any details about this.
from this website you can see the barcode reader which i purchased.

http://www.svbinternational.com/bar_code_scanners/bar_code_scannerusb.htm

model: SVB-0006

[Frinavale]

Hello everybody

I'm developing application using visual C#, and also using Barcode reader connected to USB port, some time i need to stop the barcode reader from reading when the cursor will be in another TextBox, for example when it is inside the price TextBox i don't want it to work.
Please if you have any information it will be helpful to me.
thanks in advance to all of you.

A barcode reader is an external device that will do it's own thing when certain events trigger it to process things (like when it is presented with a barcode).

I don't think that you'll be able to stop this from happening.

-Frinny

[Plater]

If the barcode acts like a keyboard, you need to research ways to disable keyboards(perferably a desired keyboard and not all keyboard) or look for ways to disable USB-DEVICES in general.
I would guess that it sends windows messages with the key strokes just the way the real keyboard does, so it would be hard to tell the difference.


On the DriveInfo class, I was unaware of that (DriveInfo.GetDrives() might be better then polling through a letter array). I would be interested to see if this recognizes drives that are mounted to a directory and not a drive letter.