Re: Help with drawing [modified] - C# Discussion Boards

Henry Minute28-Apr-09 0:32

28-Apr-09 0:32

If you are drawing directly onto the surface of the Form you need to put your code in the Paint event handler of the Form.

Just in case you don't know how to do that. Make sure your Form is selected in the designer, then in the properties window, click the events button (at the top, lightening bolt), then double-click on the Paint item. A handler stub is created in the editor, put your code there.

private void MyForm_Paint(object sender, PaintEventArgs e)
{
           // Put your code here
}

By putting the code there, it guarantees that your code gets executed every time the Form is drawn, such as when it is resized.

Henry Minute

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Re: Help with drawing

Bharat Jain28-Apr-09 0:34

Bharat Jain

28-Apr-09 0:34

Hi Johnny, .

You can to use the resize event of the form , on resize event resize shape , hope you would be able to find event , events can be found using property window , there is small yellow colored , lighting shape button , it will show all event related to the selected object (in our case form , as we have kept it selected) , there You need to find resize and double click on to white space (cell) next to resize , designer will take you to event handler , where you should place your code .

Hope i have not made it more confusing , let me know if you need more information

-Regards
Bharat Jain
bharat.jain.nagpur@gmail.com

Re: Help with drawing

Rob Philpott28-Apr-09 0:56

Rob Philpott

28-Apr-09 0:56

I'd recommend not doing this directly on the form, but deriving a new control from Panel. This control you can place on your form with docking set to fill and it will resize. This way, you gain some portability in your control (for use on other forms). You can even add properties to help define the shape etc.

As far as the drawing goes, there are two handlers you're interested in OnPaint and OnResize. You can hook events for these, or if you do go down the derived control route just override them as protected overrides.

The Resize will just let you know when the control changes size - don't attempt to draw in this. I doubt you even need this really, as you've always got access to the Width and Height in the Paint method. (Actually, you may want to Invalidate() the whole control as the OnPaint handler will clip to just new areas that weren't there prior to the resize - if you need the whole shape to resize you will need to do this).

All drawing should always be done in the OnPaint method. The Width and Height tell you the dimensions. If ever you want to redraw something in Windows, Invalidate() the area and get the OnPaint method to do the drawing.

Regards,
Rob Philpott.

Re: Help with drawing

Johnny Jackson28-Apr-09 1:40

Johnny Jackson

28-Apr-09 1:40

Thanks for the help guys (and 4 not flaming Big Grin | :-D

)

I already knew about the resize and paint events and have handled them correctly (or at least i think i have)

what i specifically need help with is getting the shapes to appear with a button click (multiple shapes each on a separate button) and the resizing of the shape as the form is resized

just a note

in the resize event i have the code

this.refresh();

is that all that goes in that section or is that where i put my code to resize the shape as well?

thanks again

Re: Help with drawing

musefan28-Apr-09 2:04

musefan

28-Apr-09 2:04

you should not need to specifically handle resizing the shape if every time it is drawn it uses the width and height of the form.

In paint event...

e.Graphics.DrawElipse(Pens.Red, 0, 0, this.Width, this.Height);

In resize event...

this.Invalidate();

Can you please explain in more details what your buttons are required to do?

Life goes very fast. Tomorrow, today is already yesterday.

Re: Help with drawing

Johnny Jackson28-Apr-09 20:15

Johnny Jackson

28-Apr-09 20:15

ok, the buttons are meant to trigger the drawing of the object (shape)

I am using a static class to hold the code to draw the shape and then calling it to the form in the paint event to draw them (I think that's how to explain it)

so in the class i have

public static void Square(Graphics g)
        {
            g.DrawRectangle(Pens.Blue, 10, 10, this.width, this.height);
        }

and in the form itself i have

Draw.Triangle(e.Graphics);

so when the button called circle is pressed it triggers the command that calls upon the class to draw a circle

with the this.height and this.width how to I tell the class the height and width of the form

I hope this clears everything up, if not let me know

Re: Help with drawing

musefan28-Apr-09 22:01

musefan

28-Apr-09 22:01

Ok, i understand a little better now. Thou im not sure of your question. But i will try to explain how you should handle what you are trying to do...

You should use a class for each of your shapes (triangle, square, etc.) each of these classes should contain the properties for that shape such as location, size, colour etc. (perhaps you could use a 'shape' base class and derive your shapes from that). Each of these classes should contain a method for drawing that takes a Graphics parameter.

Then in your main class you have a collection of shapes, then in your paint event for you panel/form you simple loop the collection and call the draw method on each shape by passing the graphics instance from the paintEventArgs.

So Then all you need to do on button clicks is to create a shape, set the properties, add it to the collection, then call invalidate() for the panel/form.

Next, to accomplish the task of resizing the shapes. I assume it would be logical to resize all the shapes on the screen. So create a handler for the Resize event of the form. Then in here you can go through your collection of shapes and change the location/size as needed. You could also modify the shapes Draw method to take parameters for the width/height of the form and draw each time based on that. Then you just need to call Invalidate() in the resize event.

Hope this helps

Life goes very fast. Tomorrow, today is already yesterday.

Re: Help with drawing [modified]

Johnny Jackson28-Apr-09 22:57

Johnny Jackson

28-Apr-09 22:57

The only thing i don't understand is that I thought it would be more appropriate to use a refresh event opposed to the invalidate event you suggested, is there a significant difference in the two events?

Ok what i have from the ground up is:

A class called shapes which contains all the code for drawing the shapes

public static void Square(Graphics g)
{
    g.DrawSquare(Pens.Blue, 10, 10, this.width, this.height);
}

etc

and then in the form i have a resize event which contains the code to draw the shapes

private void DrawBoard_Paint(object sender, PaintEventArgs e)
{
    Draw.Square(e.Graphics);
}

and for the resize event I have

private void DrawBoard_Resize(object sender, EventArgs e)
{
    this.Refresh();
}

what i specifically need help with is (as said by someone else) to "call the function that you have written in the class." because it's multiple shapes being drawn and each being drawn on demand not when the app starts and I also need to pass the width and height parameter on the click event I would assume.

in a nutshell I don't know the code to cause the click event to call upon the function in the class that draws the shape as well as the code to pass the width and height to the class

Thanks in advance.

modified on Wednesday, April 29, 2009 7:13 AM

Re: Help with drawing

musefan29-Apr-09 2:27

musefan

29-Apr-09 2:27

ok so if i got you correctly...

your square function needs to have additional params for the height and width values.

your button should also call this.Invalidate() which should result in the square being drawn

Johnny Jackson wrote:
is there a significant difference in the two events?

Not entirely sure but i think Invalidate() redraws the control itself, and Refresh() redraws the control and all child controls within it.

Life goes very fast. Tomorrow, today is already yesterday.

Creating Excel

justindhas28-Apr-09 0:08

justindhas

28-Apr-09 0:08

hi,
I want to create a Excel file in server from my web application.Is it possible?can i use open office in C#?
Regards,
justindhas

Re: Creating Excel

Henry Minute28-Apr-09 0:24

Henry Minute

28-Apr-09 0:24

Which do you want, Excel or OpenOffice Calc?
You decide, then perhaps someone can help.

Converting Word 2007 document to HTML

Sudhir Mangla27-Apr-09 23:29

Sudhir Mangla

27-Apr-09 23:29

I am working on a Project (Kind of CMS). Here we want to upload the word document. And while uploading word document we need to convert them to HTML file. , need to fetch Images and stored them in local directory. Now we need to save the HTML (with Image link changes to the images saved in Local folder) in data base. In the same manner we do saving HTML while using any Rich editor.

We will be using Word 2007 documents only. Any help in this regard will be greatly appreciated.

Sudhir Mangla

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Vista UAC: run as another user with admin rights

mSh198527-Apr-09 23:22

mSh1985

27-Apr-09 23:22

I have an application with a function which needs to be run as administrator, but it needs to be the administrator of another account.

Maybe this is not clear at all, so i'll specify my question Smile | :)

user1 runs an application
user1 presses a button which results in running another application
this other application has a manifest file which says to the uac that it needs to be runned with elevated rights

But i don't want this second application to be run with elevated rights from user1, but from user2 (user2 is a domain administrator, user1 is not)

Over the shoulder credentials is turned of on every pc here, so there is no way the user1 can change to user2 (his domain administrator account).

I've been googling for a solution for this problem, but i cannot find anything useful. Is there anyone who can point me in the right direction. I only want vista to prompt me for giving a user and pasword for running this application as a domain admin..

Thanks in advance to anyone who can point me in the right direction

edit: should i have posted this under the vista forum Unsure | :~

Re: Vista UAC: run as another user with admin rights

Johnny Jackson28-Apr-09 23:09

Johnny Jackson

28-Apr-09 23:09

Yes, this is a question about Vista's UAC not the application itself

Re: Vista UAC: run as another user with admin rights

mSh198528-Apr-09 23:25

mSh1985

28-Apr-09 23:25

ok thanks, i reposted this question in the vista forum.

Reading media file from a streaming server using a basic directshow player in C#

iFarhan27-Apr-09 23:03

iFarhan

27-Apr-09 23:03

Hie developers and coders,

It will be good if i could get a source code of a player that plays files from a streaming server...something like what youtube but rather an application than an applet...i'm really stuck with using DirectShow and it's my first time...oh ya, it will be good if the player is purely directshow base in C#...as it's one of my school projects and i'm not allowed to use directx...

Thanks a million...

Han

Argument

BabyOreo27-Apr-09 22:00

BabyOreo

27-Apr-09 22:00

Can i assign some string or integer to EventArgs?
For example, i wan assign value to the following:
EventArgs e = null;

Anyone can provide some examples?
Thanks!

Re: Argument

Christian Graus27-Apr-09 22:06

Christian Graus

27-Apr-09 22:06

Buy a basic book on OO and read it. Then move on to C#. Of course you can't assign a value of a different type to the type of the object. You CAN derive from EventArgs for your own events, and add properties, but you can't change the class for a framework event, or turn an EventArgs into a number or string.

Christian Graus

Driven to the arms of OSX by Vista.

"I am new to programming world. I have been learning c# for about past four weeks. I am quite acquainted with the fundamentals of c#. Now I have to work on a project which converts given flat files to XML using the XML serialization method" - SK64 ( but the forums have stuff like this posted every day )

Re: Argument

musefan27-Apr-09 22:06

musefan

27-Apr-09 22:06

shennwooi wrote:
EventArgs e = null;

This appears to work. but why would you want to do that? what is your requirement?

shennwooi wrote:
Can i assign some string or integer to EventArgs?

No. You cant do that. Again why would you want to?

Life goes very fast. Tomorrow, today is already yesterday.

Re: Argument

CPallini27-Apr-09 22:09

CPallini

27-Apr-09 22:09

musefan wrote:
shennwooi wrote:
EventArgs e = null;
This appears to work.

Had you doubts about? Big Grin | :-D

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

Re: Argument

musefan27-Apr-09 23:01

musefan

27-Apr-09 23:01

yeah i wanted to double check it was nullable. Like i have said i dont see a use for it...

Life goes very fast. Tomorrow, today is already yesterday.

Re: Argument

CPallini27-Apr-09 23:04

CPallini

27-Apr-09 23:04

A object reference is, by definition, nullable.