Print an image

Hi,

I have created a picturebox and drawn some lines in it to build a grid :

Dim bit As New Bitmap(570, 400)
        Dim g As Graphics = Graphics.FromImage(bit)
        Dim i As Integer

        g.DrawLine(New Pen(Color.Black, 2), 5, 5, 5, 395)
        g.DrawLine(New Pen(Color.Black, 2), 5, 395, 565, 395)
        For i = 385 To 5 Step -10
            g.DrawLine(New Pen(Color.Gray), 5, i, 565, i)
        Next
        For i = 375 To 5 Step -20
            g.DrawLine(New Pen(Color.Black, 2), 0, i, 5, i)
        Next
        For i = 22 To 578 Step 17
            g.DrawLine(New Pen(Color.Gray), i, 5, i, 395)
        Next
        For i = 39 To 578 Step 34
            g.DrawLine(New Pen(Color.Black, 2), i, 395, i, 400)
        Next
pbDiagram.Image = bit

Now if I try to print the pbDiagram with this code :

Dim g As Image = pbDiagramm.Image
gr.DrawImage(g, 100, 40)

I get an error message: Image = Null
Why is that and how can I get the printing to work

Thanks

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Print an image

Alex Duncan

Hi John,
thank's for your effort. I have just solved the problem. I was drawing the lines in pbDiagramm in frmMain. Then I created a new Class clsPrint which contains the printing code. In clsPrint I declared a New frmMain to reach my pbDiagramm but by doing so I created a new pbDiagramm wich was empty resulting in the error parameters = null. Idea

Now I'm doing it like this:
In frmMain:

Dim clsPrint As New clsPrint
clsPrint.graphic = pbDiagramm.Image

in clsPrint:

Dim graph As Image
Property graphic() As Image
        Get
            Return graph
        End Get
        Set(ByVal Value As Image)
            graph = Value
        End Set
End Property

Sub PrintDiagramm()

        Dim pd As New PrintDocument
        Dim ptdlg As New PrintDialog
        AddHandler pd.PrintPage, AddressOf printpage
        With pd
            .DocumentName = "Diagramm"
        End With
        With ptdlg
            .PrinterSettings = pd.PrinterSettings
            .AllowPrintToFile = False
            .AllowSelection = False
            .AllowSomePages = True
            If .ShowDialog() = DialogResult.OK Then
                Dim pdlg As New PrintPreviewDialog
                With pdlg
                    .Document = pd
                    .Width = 700
                    .Height = 700
                    If .ShowDialog() = DialogResult.OK Then
                        pd.Print()
                    End If
                End With
            Else
                Return
            End If
        End With
End Sub

Private Sub printpage(ByVal sender As Object, ByVal e As PrintPageEventArgs)
Dim gr As Graphics = e.Graphics
Dim oImage As Image = graphic
gr.DrawImage(oImage, 100, 100)
End Sub

So now it works.And sorry for forgetting to post the complete code in my first post.

Cheers
Bruder

Docseuss
Hi Bruder,

What is gr in gr.DrawImage(g, 100, 40)
I tested your code and it is good to the line

Dim g As Image = pbDiagramm.Image

JohnChen
Print an image

Answer this question

Print an image

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Print an image

Print an image

Alex Duncan

Docseuss