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Ninja-the-Nerd wrote: drawing using .CreateGraphics()
Never do this. Open your app. Open Calculator. Drag calculator over your app. See how your painting all disappears ? That's because you used CreateGraphics. Handle the paint event of your control instead.
Ninja-the-Nerd wrote: What I'd like to know is, is there any way of getting a System.Graphics object for an Image or a Bitmap,
Graphics.FromImage
Ninja-the-Nerd wrote: when the paint event comes a-knocking?
You call CreateGraphics in a paint event ? Why ?
Christian Graus - Microsoft MVP - C++
"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )
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"You call CreateGraphics in a paint event ? Why ?"
I don't. I assure you, even 3 years of VB.NET didn't make me THAT bad. What the app does is create an instance of a class which contains a whole lot of drawing code and pass it a reference to the control it draws to.
Then it adds its own handlers for the Resize & Paint events of the control, and updates the Graphics object accordingly.
The paint event calls the drawDisplay() event, which uses the Graphics object to draw (fill) rectangles and text to the control.
The resize event is the only thing that ever calls CreateGraphics().
What I want to do is to be able to store a copy of the Image last drawn, and only necessitate that the image be redrawn when the display is scrolled. Otherwise, the paint event will simply draw the last image drawn.
I did have a Image lastImage for this, but using displayPanel.DrawToBitmap doubled my draw time and would only draw the control as a background colour.
"Graphics.FromImage"
So if I set my Graphics object like this I'll be able to use DrawString & FillRectangle to draw directly to the Bitmap in memory, then draw said Bitmap to the control using e.Graphics.DrawImage() ?
*realises how badly explained it was first time*
Ninja (the Nerd)
Confused? You will be...
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Ninja-the-Nerd wrote: So if I set my Graphics object like this I'll be able to use DrawString & FillRectangle to draw directly to the Bitmap in memory, then draw said Bitmap to the control using e.Graphics.DrawImage() ?
Correct.
Christian Graus - Microsoft MVP - C++
"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )
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Excellent. Just starting to wrestle with the limits of Image and Bitmap being different, and wondering why new Bitmap(1, 1) can be assigned to an Image. Either way, a couple of method changes ought to have the app working great. And now, I can get on with reality (or, pseudo-reality at least).
Thanks for your help.
Ninja (the Nerd)
Confused? You will be...
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Hi,
FYI: if you want to paint to the screen, do it in the Paint handler, without CreateGraphics,
as Christian said.
if you want to paint into a Bitmap, use Graphics.FromImage() and don't
forget to dispose of the Graphics as soon as you're done painting in it.
Luc Pattyn [Forum Guidelines] [My Articles]
this months tips:
- use PRE tags to preserve formatting when showing multi-line code snippets
- before you ask a question here, search CodeProject, then Google
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What's the hurry with disposing it? I'd rather keep it and use it later (memory is no object, I have something like 500MB spare on my target machine). OK, if Graphics leaks then it'll become a problem, the app will be running for 2-2.5 hours, but CreateGraphics is only called upon creation, and resizing, which will typically be done once.
Ninja (the Nerd)
Confused? You will be...
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Ninja-the-Nerd wrote: What's the hurry with disposing it? I'd rather keep it and use it later
There is no point in keeping the Graphics, it is only valid for the one Bitmap from which
it got created; if you get another Bitmap, same or diferent size, you would need another
Graphics object. And Graphics objects are expensive, they take lots of memory and occupy
some system resources that may be expensive, meaning your system may slow down significantly
or hang completely when they run low.
so by definition "once you are done painting in it" as I put it, you
should dispose of it; later on, you can save the image to disk, or paint it to the
screen, or whatever, but for these operations the Graphics you've got from FromImage
is no longer useful.
Luc Pattyn [Forum Guidelines] [My Articles]
this months tips:
- use PRE tags to preserve formatting when showing multi-line code snippets
- before you ask a question here, search CodeProject, then Google
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Hmm. Well, being a noob with GDI (or anything more complicated than FillRectangle)...I really shouldn't argue a point, but...
If I keep it;
I get to use it during the search method which scans a text source for a result and then draws a message to the screen.
I get to update the image at will, without needing to re-get the Graphics object.
I mean, it's based on the same Image which is updated on the resize event, but the Graphics object is recreated just after that for the new Image.
Like I said, I have typically, 1GB of RAM spare on my dev machine and almost 600MB, I think, on the target machine. A few Graphics objects won't kill the system. OK, if the core part of Windows runs out of memory then, oops, but I haven't hit that eventuality yet.
As for slowing down, my dev machine, 2.6GHz Core2Duo Intel with a Radeon 2600 Pro, draws a typical screen (measured inaccurately using Environment.TickCount) in 31 or 46 "Ticks". Slow code, eh.
My 2GHz AMD Athlon which is about 4 years old, has DDR and not DDR2 RAM, and a Radeon 9200 using AGP and not PCI-E...can draw exactly the same screen completing in either 0 or 15 "ticks".
  Pretty new system, compared with 4 year old technology that sits in a cold room for weeks at a time. The only thing I can think of is the old machine has very little more than XP, .NET 2, and DirectX. The new machine has a fair bit more on it but not enough for a 3x slowdown.
Ninja (the Nerd)
Confused? You will be...
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Luc Pattyn [Forum Guidelines] [My Articles]
this months tips:
- use PRE tags to preserve formatting when showing multi-line code snippets
- before you ask a question here, search CodeProject, then Google
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I have this code that is showing a least 24 pictures, i just posted the code for 6, however i would like to know how to add an event for each one instead of one for all of them.
I considered doing:
P.Click += new EventHandler(cantPictures); which will have me to code a least 24 different events, but i don't know if that would be wise to do or if there is a more effiecient way to do it.
void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
{
int totalPics = loading.cant();
while (cantPictures < totalPics)
{
PictureBox P = new PictureBox();
Bitmap imag;
if(cantPictures <= 5)
{
if (cantPictures == 0)
{
imag = new Bitmap(images[cantPictures]);
P.Image = imag;
P.Click += new EventHandler(P_Click);
P.Size = new Size(150,150);
P.SizeMode = PictureBoxSizeMode.StretchImage;
P.Location = new Point(35, 10);
constante = 35 + P.Size.Width+10;
this.Controls.Add(P);
}
else
{
imag = new Bitmap(images[cantPictures]);
P.Image = imag;
P.Click += new EventHandler(P_Click);
P.Size = new Size(150, 150);
P.SizeMode = PictureBoxSizeMode.StretchImage;
P.Location = new Point( constante, 10);
constante += 10 + P.Size.Width;
this.Controls.Add(P);
}
}
Sorry, i just reply part of this message to one person in the forum but i thought i hit email instead...
Best regards...
Luis E Tineo S
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Hi,
most, if not all, event handlers get as a first argument "object sender" which will
hold the Control that fired, so if all your P_Click delegates are connected to PictureBoxes,
just cast sender to PictureBox and you know which one got clicked...
Luc Pattyn [Forum Guidelines] [My Articles]
this months tips:
- use PRE tags to preserve formatting when showing multi-line code snippets
- before you ask a question here, search CodeProject, then Google
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Uhmm... But how can i tell which image fired up the event? I am using the same picture box to draw the images in the form... would be comparing the image from the picture box with the array of images i have???
If not would you mind writting a simple example of how to do it please?
Thanks!
Luis E Tineo S
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kingletas wrote: I am using the same picture box to draw the images in the form
I do not agree. You have a while loop in which you do P=new PictureBox(),
so yes the variable P is used over and over, but it is a new PictureBox on every iteration
of the loop.
object sender can be cast to PictureBox, it will point to the one PictureBox that you clicked,
and if you get it's Image property, you have a reference to the Image you clicked.
So you don't need a separate collection to get this working properly.
Luc Pattyn [Forum Guidelines] [My Articles]
this months tips:
- use PRE tags to preserve formatting when showing multi-line code snippets
- before you ask a question here, search CodeProject, then Google
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Luc Pattyn wrote: kingletas wrote:
I am using the same picture box to draw the images in the form
You are completely right about this, i just said it wrong. I meant it how could id the picturebox if i was using the same variable all the time...
I think i do know now how to do it .... thanks a lot... I wouldn't have done it without you!
Luis E Tineo S
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Hello,
I am using C#.net to create a win app. I need to import extreamly large files into a SQL server database? I was wondering what is the best way to go about it. I have used SqlBulkCopy althought it is fast it times out before the import is complete due to the size of the file. I am also in the process of trying a split import with SqlBulkCopy (If I have a file that is 10 records I would import the first 5 and then import the next 5). Am I on the right track?
Any suggestions would be great.
Thanks
j
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Thanks I am going to check it out!
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I have sql query in C#
SELECT Last_Date
FROM MYTABLE
WHERE Last_Date > CONVERT(DATETIME, '13.11.2007 22:43:50', 103)
Note: Last_Date column data type is datetime
Example; If my Last_Date column like this
13.11.2007 22:43:49
13.11.2007 22:43:50
13.11.2007 22:43:51
So this query return this values
13.11.2007 22:43:50
13.11.2007 22:43:51
If I change ">" operator to ">=" operator, result is same. How can I eleminate "13.11.2007 22:43:50" value? I want to get greater than (">") values.
Thanks..
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There is a micro second component, I believe. Try 22:43:50.999
Christian Graus - Microsoft MVP - C++
"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )
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Yes, its true. I know but how can I solve my problem. I think this is related about style code "103". But I don't know which style code is correct my problem. I search but I can't find.
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First of all what u need to do AFAIK is to split the datetime into three parts lik date,time and am/pm. then put the checking.this will fetch u the xact result.
Cheers
Bino
www.codepal.co.nr
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Hello,
How can I make a button's backgroundimage enabled when I clicked the button.
Normally, I wrote, button1.bacgroundimage=null; There is button's background image, firstly, I want not to show, after clicking I want to show this background image.
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Thanks for quick reply,
but, in design page, I gave one image as button's background image in properties after that when i clicking to button, i want to see this backgroundimage.(i am beginner in programming)
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Thanks so much for your answers.
I can make now.
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I need to do the following automatically.
1. Detect when or if a pocket PC is connected via USB
2. If connected, search for a specific xml file on the pocket PC
3. Copy the file to the desktop hard drive
4. Delete the file from the pocket PC
Any help or pointers to get me started would be great!
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