Printing a Windows form

[groston]

I am trying to do something that should be simple: In my vb.net Windows Form application, when the F1 key is pressed the form should be printed. I do not need confirmation dialogs or anything like that.

I tried the following code (which I found on a website or two):

Private WithEvents PrintDocument1 As PrintDocument = New PrintDocument

Private Sub frmDGVTest_KeyDown(sender As Object, e As KeyEventArgs) Handles Me.KeyDown
    If e.KeyCode = Keys.F1 Then
        AddHandler PrintDocument1.PrintPage, AddressOf Me.PrintImage
        PrintDocument1.Print()
    End If
End Sub

Private Sub PrintImage(ByVal sender As Object, ByVal ppea As PrintPageEventArgs)
    Dim bmp As New Bitmap(Me.Width, Me.Height)
    Me.DrawToBitmap(bmp, New Rectangle(0, 0, Me.Width, Me.Height))

    ppea.Graphics.DrawImage(bmp, ppea.Graphics.VisibleClipBounds)
    ppea.HasMorePages = False
End Sub

Subroutine frmDGVTest_KeyDown works just fine, but the other doesn’t work. In fact, when I try running the code, the program hangs, cannot be killed via the Task Manager, and the computer needs to be rebooted. Please fix my code!

[dday9]

Here is an official MSDN documentation on how to print a form. https://learn.microsoft.com/en-us/do...t-windows-form

Here is a modified example to fit your use case:

Public Class frmDGVTest
    Private WithEvents _printDocument As PrintDocument
    Private _memoryImage As Bitmap

    Private Sub frmDGVTest_KeyDown(sender As Object, e As KeyEventArgs) Handles MyBase.KeyDown
        If (e.KeyCode = Keys.F1) Then
            Using myGraphics = Me.CreateGraphics()
                Dim formSize = Me.Size
                _memoryImage = New Bitmap(formSize.Width, formSize.Height, myGraphics)
                Using memoryGraphics = Graphics.FromImage(memoryImage)
                    memoryGraphics.CopyFromScreen(Me.Location.X, Me.Location.Y, 0, 0, formSize)
                End Using
            End Using
        
            PrintDocument1.Print()
        End If
    End Sub

    Private Sub PrintImage(sender As Object, e As PrintPageEventArgs) Handles _printDocument.PrintPage
        e.Graphics.DrawImage(_memoryImage, 0, 0)
    End Sub
End Class

[.paul.]

WithEvents Is used to specify that a component included via code can have eventhandlers specified in code, so rather than using AddHandler…

Private Sub PrintImage(ByVal sender As Object, ByVal ppea As PrintPageEventArgs) Handles PrintDocument1.PrintPage

[groston]

Thank you dday9 and .paul. When I used the provided code, I got an error. The problem is this: I put a break point on the line 'PrintDocument1.Print()' and the debugger shows PrintDocument1 as being nothing (once I changed the name of the declared variable to match). The referenced code has the same issue - printDocument1 is never defined.

Okay - just solved the problem: the declaration should be

Private WithEvents _printDocument As New PrintDocumen

[dday9]

Yes, that was my problem. I free-typed the code and forgot to initialize the class. Thinking about it a bit more, unless you plan on changing the value of the variable, you should probably mark it as readonly too.

Private WithEvents _printDocument As PrintDocument = New PrintDocument()