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BOOK: Beginning Visual Basic 2005 ISBN: 978-0-7645-7401-6
This is the forum to discuss the Wrox book Beginning Visual Basic 2005 by Thearon Willis, Bryan Newsome; ISBN: 9780764574016
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Old July 12th, 2009, 05:25 AM
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Default I want to know this chapter 14, is someone can give me those answers???

You can see my previous questions on the Thread, I need the answers.
Also, there is a warning message, after I run this project on the page 435.
Code:
PublicSub DoMousePaint(ByVal e As MouseEventArgs)
Dim objGraphicsItem As GraphicsItem
SelectCase GraphicTool
Case GraphicTools.CirclePen
Dim objGraphicsCircle AsNew GraphicsCircle()
objGraphicsCircle.SetPoint(e.X, e.Y, GraphicSize, GraphicColor, True)
objGraphicsItem = objGraphicsCircle
EndSelect
If objGraphicsItem IsNotNothingThen        ------------------------  (Error)
GraphicsItems.Add(objGraphicsItem)
Me.Invalidate(objGraphicsItem.Rectangle)
EndIf
EndSub


Error message:
Warning 3 Variable 'objGraphicsItem' is used before it has been assigned a value. A null reference exception could result at runtime. C:\Documents and Settings\GRACE\My Documents\Visual Studio 2005\Projects\WroxPaint\WroxPaint\PaintCanvas.vb 26 12 WroxPaint

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Old July 12th, 2009, 01:09 PM
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Grace, this is just a warning. It just lets you know that if you do not set that object before this code it will fail. You could reorder the code to remove the warning but you can just ignore it since the object is set prior to the warning. Bryan


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