PrintDocument.PrintPage override

[ladyubik_sara]

I need to pass a parameter to the event PrintPage of the PrintDocument relative to my PrintPreviewDialog in some way.
I tought to inherit PrintDocument class adding to it a property with the parameter I need, creating MyPrintDocument class. Then, I would like to create MyPrintPreviewDialog class, in which I could override the Document property declaring it of MyPrintDocument type.
The problem is that the Document property is not overridable and if I declare it Shadows the PrintPageEvent doesn't raise.
Do you have a better idea? Thank you

[jmedved]

You can pass anything inherited from PrintDocument (even your MyPrintDocument) as Document. In MyPrintPreviewDialog just cast (either TryCast, DirectCast or CType) to proper type.

P.S. Notice that there is Tag property on your PrintDocument. You can pass data through it also.

[ladyubik_sara]

Hi Jmedved,
thank you for your answer. I tried the solution of casting, but probably I did something wrong, because the PrintPage Event doesn't fire. Obviously what I need to print is more than what I wirte with the following code, this is just an example.

This is the code:

Imports System.Drawing.Printing

Public Class SlimPrice_PrintDocument
    Inherits PrintDocument

    Public dimension As String

    Public Sub New(ByVal dimension As String)
        MyBase.New()
        Me.dimension = dimension
    End Sub
End Class

Public Class SlimPrice_PrintPreviewDialog
    Inherits PrintPreviewDialog

    Public Sub New(ByVal document As SlimPrice_PrintDocument)
        MyBase.New()
        Me.Document = TryCast(document, PrintDocument)
    End Sub
End Class

Public Class Example
    Public Sub PrintLabel(ByVal dimension As String)
        Dim doc As SlimPrice_PrintDocument
        Dim ppd As SlimPrice_PrintPreviewDialog

        doc = PreparePage(dimension)
        ppd = New SlimPrice_PrintPreviewDialog(doc)
        ppd.Show()
    End Sub

    Public Function PreparePage(ByVal dimension As String) As SlimPrice_PrintDocument
        Dim printDocument As SlimPrice_PrintDocument

        printDocument = New SlimPrice_PrintDocument(dimension)
        AddHandler printDocument.PrintPage, AddressOf Print_PrintPage
        Return printDocument
    End Function

    Public Sub Print_PrintPage(ByVal sender As Object, ByVal e As System.Drawing.Printing.PrintPageEventArgs)
        e.Graphics.DrawString(sender.dimension, New Font("Arial", 10), Brushes.Black, 10, 10)
        e.HasMorePages = False
    End Sub
End Class

I can find the Tag property of PrintDocument class. If I write doc.Tag the error is "Tag is not a member of PrintDocument ". Thank you so much.

[jmedved]

Hi,

Can you send small working example of that?

It is difficult to see what is wrong if not all code is there.

[ladyubik_sara]

Writing the working example I realized that the error was not in the inheritance, but in another class. Sorry and thanx for your help. It was very helpful!

[jmedved]

That usually happens.