how to create dashed line separator using iTextSharp in vb.net - itext

Question

I have gone through the custom dotted line separator example but unable
do it in visual basic is there any example in vb
I am getting following errors
1)'Dash' is already declared as 'Protected Friend dash As Single' in this class.
2)'Phase' is already declared as 'Protected Friend phase As Single' in this class.
3)'LineWidth' is not a member of 'iTextSharp.text.pdf.PdfContentByte'.
4) Variable 'Dash' is used before it has been assigned a value. A null
reference exception could result at runtime.
5) Variable 'Phase' is used before it has been assigned a value. A null
reference exception could result at runtime.
6) sub 'draw' shadows an overridable method in the base class 'DottedLineSeparator'. To override the base method, this method must be declared 'Overrides'.
Option Strict On
Option Explicit On
Imports iTextSharp.text
Imports iTextSharp.text.pdf
Imports iTextSharp.text.pdf.draw
Public Class Form1
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs)
Handles MyBase.Load
End Sub
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs)
Handles Button1.Click
Dim FileName As String = System.IO.Path.Combine
(AppDomain.CurrentDomain.BaseDirectory, "Customers.pdf")
'Dim PageSize As New iTextSharp.text.Rectangle
(iTextSharp.text.PageSize.A4)
Dim Document As Document = New Document(iTextSharp.text.PageSize.A4,
50, 10, 10, 10)
Try
PdfWriter.GetInstance(Document, New System.IO.FileStream(FileName,
System.IO.FileMode.Create))
Document.Open()
Dim separator As New CustomDashedLineSeparator()
separator.dash = 10
separator.Gap = 7
separator.LineWidth = 3
Dim linebreak As New Chunk(separator)
Document.Add(linebreak)
Document.Close()
Catch ex As Exception
MsgBox("Pdf is Created")
End Try
End Sub
End Class
Friend Class CustomDashedLineSeparator
Inherits pdf.draw.DottedLineSeparator
Protected Friend dash As Single = 5
Protected Friend phase As Single = 2.5F
Public Overridable Property Dash As Single
Get
Return Dash
End Get
Set(ByVal dash As Single)
Me.dash = dash
End Set
End Property
Public Overridable Property Phase As Single
Get
Return Phase
End Get
Set(ByVal phase As Single)
Me.phase = phase
End Set
End Property
Public Overridable Sub draw(ByVal canvas As PdfContentByte, ByVal llx As
Single, ByVal lly As Single, ByVal urx As Single, ByVal ury As Single,
ByVal y As Single)
canvas.SaveState()
canvas.LineWidth = LineWidth
canvas.SetLineDash(dash, Gap, phase)
DrawLine(canvas, llx, urx, y)
canvas.RestoreState()
End Sub
End Class

Answer 1

Visual Basic is generally case-insensitive unlike C# and Java. You have both a property and field named Dash and also the same with Phase. That's your first two errors as well as your fourth and fifth. You can fix this by renaming your fields. One common way is to just prefix them with underscores.
For the third error, you need to use the SetLineWidth() method instead of using the LineWidth property.
For your sixth error, you are trying to override a method without explicitly telling VB that you want to. To do that you need to use Overrides instead of Overridable.
Your cleaned up class should look like this:
Friend Class CustomDashedLineSeparator
Inherits iTextSharp.text.pdf.draw.DottedLineSeparator
Protected Friend _dash As Single = 5
Protected Friend _phase As Single = 2.5F
Public Overridable Property Dash As Single
Get
Return Dash
End Get
Set(ByVal dash As Single)
Me._dash = dash
End Set
End Property
Public Overridable Property Phase As Single
Get
Return _Phase
End Get
Set(ByVal phase As Single)
Me._phase = phase
End Set
End Property
Public Overrides Sub Draw(ByVal canvas As PdfContentByte, ByVal llx As Single, ByVal lly As Single, ByVal urx As Single, ByVal ury As Single, ByVal y As Single)
canvas.SaveState()
canvas.SetLineWidth(LineWidth)
canvas.SetLineDash(Dash, Gap, phase)
DrawLine(canvas, llx, urx, y)
canvas.RestoreState()
End Sub
End Class
However, I'm betting that you don't really need those internal properties in the first place. If not, you can make that class even simpler:
Friend Class CustomDashedLineSeparator
Inherits iTextSharp.text.pdf.draw.DottedLineSeparator
Public Property Dash As Single
Public Property Phase As Single
Public Overrides Sub Draw(ByVal canvas As PdfContentByte, ByVal llx As Single, ByVal lly As Single, ByVal urx As Single, ByVal ury As Single, ByVal y As Single)
canvas.SaveState()
canvas.SetLineWidth(LineWidth)
canvas.SetLineDash(Dash, Gap, phase)
DrawLine(canvas, llx, urx, y)
canvas.RestoreState()
End Sub
End Class
Lastly, please never try/catch giant blocks of code. At best, your app will politely crash however you'll have no idea why and you'll never be able to fix it. Although not as pretty "Unable to open file XYZ.pdf for writing" is way more helpful than "Unable to create PDF".