[dba-VS] Printing 'Code 128 A' Barcode Labels

[Stuart McLachlan]

On 26 Oct 2017 at 8:46, Salakhetdinov Shamil via dba wrote:

> 
> Hi All --
> 
> I have to print 'Code 128A' barcode labels in one of my customers C#
> applications' reports. Do you know any third-party tools lighter than
> LEADTools ( https://www.leadtools.com/sdk/barcode-pro ) to solve my
> task?
> 
> FYI: I have googled and I have found several solutions but all of them
> look a bit ovewrpriced for a single task of just printing barcode
> labels.
> 
> There seems to be also a free solution
> (https://www.codeproject.com/Articles/14409/GenCode-A-Code-Barcode-Gen
> erator) but I'm not sure it will be useful for my case where I'll have
> to print several labels in two columns in one A4 page.
>
Does hit have to be Subset A?  (i.e. with ASCII Control characters).  If you are only after 
letters and numbers, then the simplest solution is to download a Code128 font and write a 
function to covert your data to an appropriate string.

If you need to use A, it gets a bit more tricky.

Here's a Code 128 TTF: https://d13ot9o61jdzpp.cloudfront.net/files/code128.ttf

And here's a VBA function to convert a string to a Code128 (B or C) string.  (I'm sure you can 
covert it to C# fairly easily)  

Public Function Code128(SourceString As String)
  
    'Written by Philip Treacy, Feb 2014
    'http://www.myonlinetraininghub.com/create-barcodes-with-excel-vba
    'This code is not guaranteed to be error free.  No warranty is implied or expressed. Use at 
your own risk and carry out your own testing
    'This function is governed by the GNU Lesser General Public License (GNU LGPL) Ver 3
    'Input Parameters : A string
    'Return : 1. An encoded string which produces a bar code when dispayed using the 
CODE128.TTF font
    '         2. An empty string if the input parameter contains invalid characters
  
    Dim Counter As Integer
    Dim CheckSum As Long
    Dim mini As Integer
    Dim dummy As Integer
    Dim UseTableB As Boolean
    Dim Code128_Barcode As String
  
    If Len(SourceString) > 0 Then
  
        'Check for valid characters
        For Counter = 1 To Len(SourceString)
    
            Select Case Asc(Mid(SourceString, Counter, 1))
        
                Case 32 To 126, 203
            
                Case Else
            
                    MsgBox "Invalid character in barcode string." & vbCrLf & vbCrLf & "Please only 
use standard ASCII characters", vbCritical
                    Code128 = ""
                    Exit Function
            
            End Select
        
        Next
    
        Code128_Barcode = ""
        UseTableB = True
    
        Counter = 1
        Do While Counter <= Len(SourceString)
        
            If UseTableB Then
                
                'Check if we can switch to Table C
                mini = IIf(Counter = 1 Or Counter + 3 = Len(SourceString), 4, 6)
                GoSub testnum
                
                If mini% < 0 Then 'Use Table C
            
                    If Counter = 1 Then
                
                        Code128_Barcode = Chr(205)
                
                    Else 'Switch to table C
                
                        Code128_Barcode = Code128_Barcode & Chr(199)
                    
                    End If
                
                    UseTableB = False
            
                Else
            
                    If Counter = 1 Then Code128_Barcode = Chr(204) 'Starting with table B
            
                End If
            
            End If
        
            If Not UseTableB Then
            
                'We are using Table C, try to process 2 digits
                mini% = 2
                GoSub testnum
          
                If mini% < 0 Then 'OK for 2 digits, process it
            
                    dummy% = Val(Mid(SourceString, Counter, 2))
                    dummy% = IIf(dummy% < 95, dummy% + 32, dummy% + 100)
                    Code128_Barcode = Code128_Barcode & Chr(dummy%)
                    Counter = Counter + 2
                
                Else 'We haven't got 2 digits, switch to Table B
            
                    Code128_Barcode = Code128_Barcode & Chr(200)
                    UseTableB = True
                
                End If
        
            End If
        
            If UseTableB Then
        
                'Process 1 digit with table B
                Code128_Barcode = Code128_Barcode & Mid(SourceString, Counter, 1)
                Counter = Counter + 1
            
            End If
        
        Loop
        
        'Calculation of the checksum
        For Counter = 1 To Len(Code128_Barcode)
        
            dummy% = Asc(Mid(Code128_Barcode, Counter, 1))
            dummy% = IIf(dummy% < 127, dummy% - 32, dummy% - 100)
            
            If Counter = 1 Then CheckSum& = dummy%
                
            CheckSum& = (CheckSum& + (Counter - 1) * dummy%) Mod 103
                
        Next
      
        'Calculation of the checksum ASCII code
        CheckSum& = IIf(CheckSum& < 95, CheckSum& + 32, CheckSum& + 100)
      
        'Add the checksum and the STOP
        Code128_Barcode = Code128_Barcode & Chr(CheckSum&) & Chr$(206)
    End If
  
    Code128 = Code128_Barcode
  
    Exit Function

    
testnum:
    
        'if the mini% characters from Counter are numeric, then mini%=0
        mini% = mini% - 1
        If Counter + mini% <= Len(SourceString) Then
    
            Do While mini% >= 0
        
                If Asc(Mid(SourceString, Counter + mini%, 1)) < 48 Or Asc(Mid(SourceString, 
Counter + mini%, 1)) > 57 Then Exit Do
                mini% = mini% - 1
            
            Loop
        
        End If
    
        Return
    
End Function