PrintForm bug with MDI code

I have an mdi application into which I slotted PrintForm. This seemd to work well until suddenly I was getting only part of the form printed or previewed. Further testing revealed that this only happens when the mdi container is NOT maximised AND the PrinterOption is ClientAreaOnly or Scrollable (or CompatModeCAO). What appears to be printed is the portion of the form that falls into the rectangle that equates to the position of the form if the mdi container was maximised.

It’s easy to replicate this.

- Start a new windows application project in Visual Studio

- Change Form1’s IsMdiContainer to True

- Make the form quite a bit bigger than the default (so there’s no implication of scrolling problems later on)

- Add a button (unconventional, but quick and easy).

- Add a second form

- Add the PrintForm component to Form2

- Add a button to Form2

- Double click the button to create a click event handler

- Add the line
PrintForm1.PrintAction = Printing.PrintAction.PrintToPreview
PrintForm1.Print(Me, PowerPacks.Printing.PrintForm.PrintOption.ClientAreaOnly)

- Back to Form1 and double click the button to create a click event handler

- Add the lines
Dim f As New Form2

f.MdiParent = Me

f.Show()

- Run the application

- Make sure it isn’t maximised or at the very top left of the Windows Desktop

- Click the button on Form1 to launch Form2

- Click the button on Form2 to display the Print Preview

- Only a small portion of the form will be shown in the Preview

I found a workaround for this, which is to detatch Form2 from the mdi container for the duration of the Preview. In the above code that can be done by replacing the Form2 Button1 click event code with:

- Dim pf As Form = MdiParent

MdiParent = Nothing

PrintForm1.PrintAction = Printing.PrintAction.PrintToPreview

PrintForm1.Print(Me, PowerPacks.Printing.PrintForm.PrintOption.ClientAreaOnly)

MdiParent = pf

This works a treat. However, when I did this in my real application I got the problem that the Form (equivalent to Form2 above) jumps to a different location whilst it is detatched from the mdi container. To get around this, I had to find the real screen coordinates and force the form to use those whilst the PrintForm was active. I also had to refresh the controls, or the display was a mess of half drawn controls. Here’s what worked for me, using the code from my real application.

' PrtForm is in effect “Me”, passed into this code

Dim parentForm As Form = PrtForm.MdiParent

Dim absoluteLocation As System.Drawing.Point = _
PrtForm.ParentForm.PointToScreen(New System.Drawing.Point _
(PrtForm.Location.X + 2, PrtForm.Location.Y + 2))

Dim saveLocation As System.Drawing.Point = PrtForm.Location

' hide form whilst we fiddle

PrtForm.Hide()

PrtForm.MdiParent = Nothing

Dim saveMenu As MainMenu = PrtForm.Menu

PrtForm.Menu = Nothing

PrtForm.Location = absoluteLocation

' now reshow it and refresh the controls

PrtForm.Show()

PrtForm.Refresh()

PrintForm1.Print(PrtForm, PowerPacks.Printing.PrintForm.PrintOption.Scrollable)

' put everything back !!

PrtForm.Hide()

PrtForm.Location = saveLocation

PrtForm.Menu = saveMenu

PrtForm.MdiParent = parentForm

PrtForm.Show()

I hope this helps somebody !!