[abuzzouz]

أخي مصطفى سؤالك غير واضح.. لكن إليك الجواب كما فهمت

كود :

Dim dbConn As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0; Data Source=" & Application.StartupPath & "\DataFile.mdb")
        Dim SQLStr As String = "Select Field from Table"
        Conn.Open()
        Dim cmd As New OleDb.OleDbCommand(SQLStr, Conn)
        dr = cmd.ExecuteReader
        Try
            If dr.Read = True Then
                MsgBox("The Barcode is Exist >>")
            End If
            Conn.Close()
        Catch ex As Exception
            Conn.Close()
            MsgBox(ex.Message, MsgBoxStyle.Critical, " Error")
        End Try

طبعاً قاعدة البيانات هنا من نوع Access