主题：逐行显示条码的程序报错，请问如何修改

Dim doc As New PrintDoc
Dim img As prt.RenderImage
Dim Bar As New BarCodeBuilder
Dim rg As New prt.RenderGraphics
Bar.Symbology = Barpro.Symbology.Code128
Bar.BarRatio = 0.3
Bar.BarHeight = 8
'Doc.Stacking = prt.StackingRulesEnum.InlineLeftToRight

For i As Integer = 1 To 4
    bar.Code = "12345678901234567890"
   
    rg = new prt.RenderGraphics
    'rg.X = 10
    'rg.Y = 25
    bar.BarRatio = 0.8
    bar.BarHeight = 12
    bar.BarWidth = 0.3
    bar.DisplayCode =False
    bar.DrawOnCanvas(rg.Graphics,0,0,1)
  
    Doc.Body.Children.Add(rg)
Next

Doc.Preview()