You can generate and output the code128 images in VB programming with this code . Refer to the following Visual Basic sample code,you can try to generate code128 in vb.net.
VB Sample code
Dim code128 As KeepAutomation.Barcode.Bean.BarCode = New KeepAutomation.Barcode.Bean.BarCode
code128.Symbology = KeepAutomation.Barcode.Symbology.Code128Auto
code128.CodeToEncode = "0128"
'Apply checksum for Code 128 barcode.
code128.ChecksumEnabled = True
'Display checksum in the Code 128 barcode text
code128.DisplayChecksum = True
'Unit of measure, Pixel, Cm and Inch supported.
code128.BarcodeUnit = KeepAutomation.Barcode.BarcodeUnit.Pixel
'Code 128 image resolution in DPI.
code128.DPI = 72
'Set Size for Generated Code 128 image
'Code 128 bar module width (X dimention)
code128.X = 2
'Code 128 barcode image width (X dimention)
code128.BarCodeWidth = 100
'Code 128 bar module height (Y dimention)
code128.Y = 60
'Image left margin size, a 10X is automatically added according to specification.
code128.LeftMargin = 0
'Image right margin size, a 10X is automatically added according to specification.
code128.RightMargin = 0
'Code 128 image top margin size'
code128.TopMargin = 0
'Code 128 image bottom margin size'
code128.BottomMargin = 0
'Orientation, 90, 180, 270 degrees supported' Code 128 image bottom margin size
code128.Orientation = KeepAutomation.Barcode.Orientation.Degree0
'Code 128 image formats in Png, Gif, Jpeg/Jpg, Tiff, Bmp/Bitmap, etc.
code128.ImageFormat = System.Drawing.Imaging.ImageFormat.Png
'Set Code 128 human readable text style
code128.DisplayText = True
code128.TextFont = New Drawing.Font("Arial", 10.0F, Drawing.FontStyle.Regular)
'Space between barcode and text
code128.TextMargin = 6
code128.generateBarcodeToImageFile("C://code128-vb-net.png")