473,702 Members | 2,450 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

using g.DrawRectangle (pen,rect) to draw a rectangle on an object

Hi there. I have written a small procedure to draw various shapes on
things. A bit of it is shown below.

Private Sub drawShape(ByVal shapeType As Integer, ByRef g As Graphics)
Select Case shapeType
Case 1 : g.DrawRectangle (New Pen(Color.Black ), 0, 0, 50, 10)
Case 2 'draw a circle
Case 3 'draw a triangle
Case 4 'draw other shape
Case 5 'draw other shape
Case 6 'draw other shape
Case Else 'etc. draw other shapes
End Select
End Sub

If on Form1, I override the OnPaint method with

Protected Overrides Sub OnPaint(ByVal e As
System.Windows. Forms.PaintEven tArgs)
MyBase.OnPaint( e)
drawShape(1, e.Graphics)
End Sub

it paints my rectangle as I would expect drawing it on Form1 at 0,0
with width 50 and height 10.

I have lots of other controls on the form, such as buttons, labels,
groupboxes etc. My question is how do I get 'g' (a valid Graphics
instance) for the buttons, labels, groupboxes and other things.

The obvious thing I tried below doesn't work (I see no rectangle on
the GroupBox, called GroupBox1) but still see the rectangle on the
form. I want to see both.

Protected Overrides Sub OnPaint(ByVal e As
System.Windows. Forms.PaintEven tArgs)
MyBase.OnPaint( e)
drawShape(1, e.Graphics)
drawShape(1, Me.GroupBox1.Cr eategraphics())
End Sub
Thank you in advance for all your help and sorry to post more of these
verbose and tricky questions.
Colin
Nov 20 '05 #1
3 10321
Colin - you have come a long way judging by the type of questions you are
now asking.

I'm not going to answer your question directly but provide you with some
information that should enable you to work out the answer to your question
yourself.

If Panel1 is a Panel on your form, TabControl1 is a TabControl on your form,
and Button1 is a Button on your form, when OnPaint is executed

Protected Overrides Sub OnPaint(ByVal e As
System.Windows. Forms.PaintEven tArgs)
MyBase.OnPaint( e)
Dim g As Graphics = Panel1.CreateGr aphics()
drawShape(1, g)
g.Dispose()
g=TabControl1.C reateGraphics()
drawShape(1,g)
g.Dispose()
g=Button1.Creat egraphics()
drawShape(1,g)
g.Dispose()
End Sub

you will see your blue rectangle on both Panel1 and TabControl1, but not
Button1. Ask yourself why the rectangle draws on some form objects but not
others - what is different about them and how would/could you change the
observed behaviour.

Regards
Hexathioorthoox alate
PS: Here's an excerpt from the on-line (VB.NET 2003) docs for
CreateGraphics. Quote: "The returned Graphics object must be disposed
through a call to its Dispose method when it is no longer needed.". Your use
of drawShape(1, Me.GroupBox1.Cr eategraphics()) doesn't and can't dispose of
the graphics object as written.


"Colin McGuire" <co***********@ lycos.co.uk> wrote in message
news:ab******** *************** ***@posting.goo gle.com...
Hi there. I have written a small procedure to draw various shapes on
things. A bit of it is shown below.

Private Sub drawShape(ByVal shapeType As Integer, ByRef g As Graphics)
Select Case shapeType
Case 1 : g.DrawRectangle (New Pen(Color.Black ), 0, 0, 50, 10)
Case 2 'draw a circle
Case 3 'draw a triangle
Case 4 'draw other shape
Case 5 'draw other shape
Case 6 'draw other shape
Case Else 'etc. draw other shapes
End Select
End Sub

If on Form1, I override the OnPaint method with

Protected Overrides Sub OnPaint(ByVal e As
System.Windows. Forms.PaintEven tArgs)
MyBase.OnPaint( e)
drawShape(1, e.Graphics)
End Sub

it paints my rectangle as I would expect drawing it on Form1 at 0,0
with width 50 and height 10.

I have lots of other controls on the form, such as buttons, labels,
groupboxes etc. My question is how do I get 'g' (a valid Graphics
instance) for the buttons, labels, groupboxes and other things.

The obvious thing I tried below doesn't work (I see no rectangle on
the GroupBox, called GroupBox1) but still see the rectangle on the
form. I want to see both.

Protected Overrides Sub OnPaint(ByVal e As
System.Windows. Forms.PaintEven tArgs)
MyBase.OnPaint( e)
drawShape(1, e.Graphics)
drawShape(1, Me.GroupBox1.Cr eategraphics())
End Sub
Thank you in advance for all your help and sorry to post more of these
verbose and tricky questions.
Colin

Nov 20 '05 #2
Hex - thanks for your help.

The Panel etc are .Net controls, and the Button is a Windows control?
But I still want to draw on the Button too. How?
Thank you
Colin.
Nov 20 '05 #3
Hex isnt online today. Could someone else help me out here please.

I can see that rectangles are only drawn on objects that are not
Windows controls (such as buttons and textboxes).

How can I tell as a general rule whether the object is drawn by the
framework and not by Windows? Currently a "GroupBox" is drawn by the
framework but what if Microsoft modify Windows so that it is drawn
there - then my code won't work. So what I think I want it a
subroutine to pass a object (like a button, or a panel, or a
groupbox), and the subroutine print out whether the object is drawn by
Windows or the framework (and therefore whether my blue rectangle,
code below, will be drawn).
Thank you
Colin
"Hexathioorthoo xalate" <ru***@spamerem ove.clara.co.uk > wrote in message news:<10******* *********@damia .uk.clara.net>. ..
Colin - you have come a long way judging by the type of questions you are
now asking.

I'm not going to answer your question directly but provide you with some
information that should enable you to work out the answer to your question
yourself.

If Panel1 is a Panel on your form, TabControl1 is a TabControl on your form,
and Button1 is a Button on your form, when OnPaint is executed

Protected Overrides Sub OnPaint(ByVal e As
System.Windows. Forms.PaintEven tArgs)
MyBase.OnPaint( e)
Dim g As Graphics = Panel1.CreateGr aphics()
drawShape(1, g)
g.Dispose()
g=TabControl1.C reateGraphics()
drawShape(1,g)
g.Dispose()
g=Button1.Creat egraphics()
drawShape(1,g)
g.Dispose()
End Sub

you will see your blue rectangle on both Panel1 and TabControl1, but not
Button1. Ask yourself why the rectangle draws on some form objects but not
others - what is different about them and how would/could you change the
observed behaviour.

Regards
Hexathioorthoox alate
PS: Here's an excerpt from the on-line (VB.NET 2003) docs for
CreateGraphics. Quote: "The returned Graphics object must be disposed
through a call to its Dispose method when it is no longer needed.". Your use
of drawShape(1, Me.GroupBox1.Cr eategraphics()) doesn't and can't dispose of
the graphics object as written.


"Colin McGuire" <co***********@ lycos.co.uk> wrote in message
news:ab******** *************** ***@posting.goo gle.com...
Hi there. I have written a small procedure to draw various shapes on
things. A bit of it is shown below.

Private Sub drawShape(ByVal shapeType As Integer, ByRef g As Graphics)
Select Case shapeType
Case 1 : g.DrawRectangle (New Pen(Color.Black ), 0, 0, 50, 10)
Case 2 'draw a circle
Case 3 'draw a triangle
Case 4 'draw other shape
Case 5 'draw other shape
Case 6 'draw other shape
Case Else 'etc. draw other shapes
End Select
End Sub

If on Form1, I override the OnPaint method with

Protected Overrides Sub OnPaint(ByVal e As
System.Windows. Forms.PaintEven tArgs)
MyBase.OnPaint( e)
drawShape(1, e.Graphics)
End Sub

it paints my rectangle as I would expect drawing it on Form1 at 0,0
with width 50 and height 10.

I have lots of other controls on the form, such as buttons, labels,
groupboxes etc. My question is how do I get 'g' (a valid Graphics
instance) for the buttons, labels, groupboxes and other things.

The obvious thing I tried below doesn't work (I see no rectangle on
the GroupBox, called GroupBox1) but still see the rectangle on the
form. I want to see both.

Protected Overrides Sub OnPaint(ByVal e As
System.Windows. Forms.PaintEven tArgs)
MyBase.OnPaint( e)
drawShape(1, e.Graphics)
drawShape(1, Me.GroupBox1.Cr eategraphics())
End Sub
Thank you in advance for all your help and sorry to post more of these
verbose and tricky questions.
Colin

Nov 20 '05 #4

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

6
17209
by: Joe Kelsey | last post by:
When you use addEventListener (or addEvent in IE) to call an object method, does it call it with the correct this parameter? The ECMAScript reference has a lot to say about the caller using Function.prototype.call or Function.prototype.apply and passing the correct this pointer for the context, but how does addEventListener determine the correct this pointer. Or does it just punt and pass the global context, thus making it impossible to...
7
1498
by: William Apple | last post by:
Despite the fact this deals with webservices I believe it is a VB question. I am working on a test application that passes data to a webservice. The webservices takes a variable type that is defined below: Public Class Variable Inherits MarshalByRefObject '<remarks/> Public strVariableName As String
1
2899
by: Ram | last post by:
Hi All, I am using Object Data Source to bind data in the gridview. I have set the property AllowSorting=true. While running the application, I could sort the data only in ascending order. Is there any way to achieve two way sorting in gridview ie. both ascending and descending on successive clicks ?. Please give me a suggestion to solve this issue. Thanks in advance.
6
1882
by: burningodzilla | last post by:
Hi all - I'm preparing to dive in to more complex application development using javascript, and among other things, I'm having a hard time wrapping my head around an issues regarding "inheritance" using the prototype property. I realize there are no classes in JS, that code therefore lives in objects instead of class definitions, and that "inheritance" must be achieved prototypically and not classically. That said, on with the code. Say I...
0
1388
by: sajithamol | last post by:
I have a dll of a VB application which performs image manipulations. I want to build this dll file into a .cab file to embed this in the Object tag in client side. Also how to generate the classid for the .cab file which is a required parameter for using Object tag.
2
1850
by: Veloz | last post by:
Hiya My question is whether or not you should associated related objects in your software using a scheme of id's and lookups, or wether objects should actually hold actual object references to objects they are associated with. For example, lets say you are modelling studen ratings of teachers. Let's say your applications needs to analyze these ratings for teachers and is provided a data file. In this data file the teachers all have...
1
1444
by: busiswa | last post by:
Hi All, I am just new in PHP, i am asked to draw a combobox using the draw() method. Can someone help me on how to go about that. Thank you, Busi
9
1261
by: Duggi | last post by:
I used to wonder why MS implemented C# to accept the following code using (Font f = new Font()) { // some code here. } While the same can be achieved through {
12
1567
by: Duggi | last post by:
I used to wonder why MS implemented C# to accept the following code using (Font f = new Font()) { // some code here. } While the same can be achieved through {
0
8738
marktang
by: marktang | last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, weíll explore What is ONU, What Is Router, ONU & Routerís main usage, and What is the difference between ONU and Router. Letís take a closer look ! Part I. Meaning of...
1
8979
by: Hystou | last post by:
Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
0
8939
tracyyun
by: tracyyun | last post by:
Dear forum friends, With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the choice of these technologies. I'm particularly interested in Zigbee because I've heard it does some...
0
5907
by: conductexam | last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...
0
4412
by: TSSRALBI | last post by:
Hello I'm a network technician in training and I need your help. I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs. The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols. I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
0
4667
by: adsilva | last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
1
3104
by: 6302768590 | last post by:
Hai team i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system
2
2399
muto222
by: muto222 | last post by:
How can i add a mobile payment intergratation into php mysql website.
3
2036
bsmnconsultancy
by: bsmnconsultancy | last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.