Read a single value from a query with VB.Net

Sometimes it's necessary to read single value from a table (or a query). Here's the code:

Imports System.Data.Oledb

Dim ConnString As String = "connection string"

' open connection

Dim Conn As New Data.OleDb.OleDbConnection(ConnString)

Cn.Open()

' request execution

Dim SQL As String = "SELECT Data FROM Table WHERE ID = 'aaaa';"

Dim command As New Data.OleDb.OleDbCommand(Sql, Conn)

Dim ID As Integer = command.ExecuteScalar()

'close connection

Cn.Close()

Image to byte array conversion

It's very easy to convert an image into a byte array, with VB.NET; using MemoryStream object:

Private Function ConvertImageToByteArray(ByVal inputImage As Image) As Byte()

    Dim ms As New System.IO.MemoryStream

    inputImage.Save(ms, System.Drawing.Imaging.ImageFormat.Bmp)

    Return ms.ToArray

End Function

To re-convert the byte array into image, we can use ImageConverter class:

Private Function ConvertByteArrayToBitmap(ByVal array As Byte()) As Bitmap

    Dim ic As New ImageConverter

    Dim img As Image = CType(ic.ConvertFrom(array), Image)

    Dim bmp As New Bitmap(img)

    Return bmp

End Function

Email address validation with Vb.net and Regula Expression

Imports System.Text.RegularExpressions

Dim ValidateMail As String = "^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-z]{2,4}|[0-9]{1,3})(\]?)$"

Dim EmailAddress As String = "$mymail@domain.com$"

If Regex.IsMatch(EmailAddress, ValidateMail) Then
...
Else
...
End If

Mounting CdRom on SCO/Unix

After the creation of the folder as mount point with mkdir    /mnt/cdrom, we have to find the "phisycal" name of cdrom unit. To do it, go to device folder with

cd   /dev/cdrom

and then type

ls

to view the name. For this example, assume c0b0t6l0 as the device name

So, the mount command is:

mount   -r   -F   cdfs   /dev/cdrom/c0b0t6l0   /mnt/cdrom