|
Hello.
I have a simple picturebox where there is a image loaded in
Im drawing a rectangle on the picturebox and when I press a button I want to invalidate it (remove the rectangle), but it doesnt seem to work
The rectangle is drawn fine and the image loads up to, but when I press my button nothing happens
Here is the code im using:
private void drawOnPic()<br />
{<br />
Graphics g = Graphics.FromImage(pictureBox1.Image);<br />
<br />
Pen PenStyle = new Pen(Color.Red, 1);<br />
<br />
g.DrawRectangle(PenStyle, 20, 20, 50, 50);<br />
}<br />
<br />
private void button1_Click(object sender, EventArgs e)<br />
{<br />
pictureBox1.Invalidate();<br />
}<br />
<br />
private void Form1_Load(object sender, EventArgs e)<br />
{<br />
drawOnPic();<br />
}
|
|
|
|
|
Hi,
Graphics.FromImage(pictureBox1.Image); gives you access to the internals of
the image the PB is showing. g.DrawRectangle(...); modifies this image;
such modification is irreversible, invalidating the PB only tells it to repaint itself,
hence showing the modified image again.
If you want to be able to undo graphic stuff,
either paint on top of the PB (using its OnPaint handler)
or keep a copy of the original image, so you can restore it (PB.Image=oldImage;).
Luc Pattyn [Forum Guidelines] [My Articles]
This month's tips:
- before you ask a question here, search CodeProject, then Google;
- the quality and detail of your question reflects on the effectiveness of the help you are likely to get;
- use PRE tags to preserve formatting when showing multi-line code snippets.
|
|
|
|
|
In these days, in our project ,I must develop a logon page use c# language, it's a windows form project,for example:
1 The userName textbox coule only accept letter and numer digits ,and it exclude "@#$%&*(^_|" ,etc.
2 the roomid textbox could only accept the numeric digit ,but when the user input is 1.02,32.0,33.8 ,etc, which is not i expect.
Hao can i do ,any help is appreciated!
thank you very much .
|
|
|
|
|
either use a MaskedTextbox or use a regular TextBox and let the KeyPress handler reject
all characters you don't want (you probably should allow all char.IsControl so BACKSPACE
and CTRL/C and CTRL/V remain operational).
All the details (as well as the above) can be found in the documentation; and Google is a
nice way of locating it.
Luc Pattyn [Forum Guidelines] [My Articles]
This month's tips:
- before you ask a question here, search CodeProject, then Google;
- the quality and detail of your question reflects on the effectiveness of the help you are likely to get;
- use PRE tags to preserve formatting when showing multi-line code snippets.
|
|
|
|
|
hey guys
i have a URL saved in a string like http://codeproject.com/something.htm
i'd only like to select the domain name part of it (codeproject.com)
how can i do it?
page link can also be http://www.code... or www.code...
thank you
|
|
|
|
|
Create a Uri object with your stored string. Then access the Host property.
Example:
Uri url = new Uri("http://www.codeproject.com");<br />
string domainName = url.Host;
Ryan Bost
|
|
|
|
|
wow! i was never knew about Uri!
thank you so much!
|
|
|
|
|
Is it possible to make the soapformatter ignore missing fields?
Eg if the file have been saved in a previous format and I later try to deserialize it into a new format where not all fields match 100%
Im aware of [OptionalField], but that is the opposite of what I want.
Optional lets me introduce new fields into my format.
I want to simply ignore old fields that are not used any more.
And I also know that I can implement ISerializable, but I do not want that, I just want to use the default mechanism but ignoring missing fields.
(last resort would be to roll my own formatter, but im trying to avoid that)
|
|
|
|
|
Hello all,
Does anybody knows how to change the default caption text in the ColorDialog component of .Net 2.0? Default it is set to "Color", while I want to be able to change this into: "Select foreground color".
With regards,
EiSl
|
|
|
|
|
How do I publish an XNA project? I want to be able to send it in an eMail.
- I love D-flat!
- Need. More. Code.
modified on Saturday, April 5, 2008 6:29 PM
|
|
|
|
|
Repost your question here
|
|
|
|
|
I did.
- I love D-flat!
- Need. More. Code.
|
|
|
|
|
Hi. I need to take a screen shot of a control - the control is plotterForm.expressionPlotter. I am using the following code:
<br />
private Bitmap GetBitmap()<br />
{<br />
Bitmap bmp = new Bitmap(plotterForm.expressionPlotter.Width, plotterForm.expressionPlotter.Height);<br />
Graphics g = Graphics.FromImage(bmp);<br />
Screen screen = Screen.FromControl(plotterForm.expressionPlotter);<br />
g.CopyFromScreen(new Point(screen.Bounds.Location.X, screen.Bounds.Location.Y), Point.Empty, plotterForm.expressionPlotter.Size);<br />
return bmp;<br />
}
The problem is that the location of which the screen shot is always the upper left corner of the desktop, not the upper left corner of the control.
In other words the screen.Bounds.Location is a point which is always (0;0). When i added MessageBox.Show(screen.ToString()); i received the following message:
Screen[Bounds={X=0,Y=0,Width=1024,Height=768} WorkingArea={X=0,Y=0,Width=1024,Height=739} Primary=True DeviceName=\\.\DISPLAY1
As if the screen hasn't captured the control. How can i fix this???
Still learning...
|
|
|
|
|
I realized that the Screen.FromControl is something entirely different from the thing i expected! But here comes another question - how can i find the location of a control in relation to the desktop?
Still learning...
|
|
|
|
|
Use...
PointToScreen(control.Location);
Matthew Butler
|
|
|
|
|
Can you not just use DrawToBitmap as in:
int height = plotterForm.expressionPlotter.Height;
int width = plotterForm.expressionPlotter.Width;
Bitmap bmp = new Bitmap(width, height);
plotterForm.expressionPlotter.DrawToBitmap(bmp, new Rectangle(0,0,width,height));
Because if you could i imagine it will be much easier.
My current favourite word is: Nipple!
-SK Genius
|
|
|
|
|
I changed the code of the project a little bit and the control which i want to capture is a panel. The panel has a written text using the DrawString method of the Graphics class.The screen shot is stored in the clipboard. When i take a screen shot using DrawToBitmap , when i paste the image in paint it appears, but the text isn't there.
The taken screen shot[^]
The image as it should be[^]
Why doesn't the DrawToBitmap method capture the text???
Still learning...
|
|
|
|
|
i don't know, i had trouble with a textbox not drawing the text when i used DrawToBitmap. Then all of a sudden it just started working. and i'm not sure why/
My current favourite word is: Nipple!
-SK Genius
|
|
|
|
|
Take a screen shot of the whole screen and then use an image editor?
Or, what I did was write a simple applet that I can position over the section of the screen I want to capture and have do the capture.
|
|
|
|
|
Im 99% sure that the DrawToBitmap method will invoke the OnPaint method on the control and pass a graphics object containing the bitmap.
so if you draw the text outside of the OnPaint method, that code will not be triggered when calling DrawToBitmap.
How are you drawing the text?
Control.CreateGraphics?
|
|
|
|
|
This is how things are:
I have created a control - ExpressionPlotter . It is used to plot math graphs - they are drawn on the control. The control has a panel which contains the graphs' information. In the OnPaint method of the ExpressionPlotter is the method which draws the text - DisplayExpressionsText . In DisplayExpressionsText the panel is sized according to the text and then in the drawing of the text the method panel.CreateGraphics is used to obtain the Graphics class. When it comes to the screen shot the DrawToBitmap is called for the ExpressionPlotter control.
I tried to draw the text in the Paint event of the panel, but when i started the program, the panel didn't show.
Still learning...
|
|
|
|
|
I did it! I moved the resizing of the panel to the OnPaint . Then i moved the drawing of the text to the Paint event of the panel. When i want to draw the text now i only have to Refresh() the panel.
Still learning...
|
|
|
|
|
nike_arh wrote: in the drawing of the text the method panel.CreateGraphics is used to obtain the Graphics class.
That's your problem. That means that you are always drawing the text on the screen. Use the Graphics object that is supplied in the event arguments to the Paint event.
Despite everything, the person most likely to be fooling you next is yourself.
|
|
|
|
|
Take a look at my article clickety in which I cover basic screen capture as well as capturing a specific area of the screen.
The source code is available for download from the article as well.
Regards
Guy
You always pass failure on the way to success.
|
|
|
|
|
When I open report by click button event - on the first time it opens, but on the second time (when I close report and open again), app breaks and appears error message:
System.InvalidOperationException was unhandled
Message="Invoke or BeginInvoke cannot be called on a control until the window handle has been created."
Source="System.Windows.Forms"
StackTrace:
at System.Windows.Forms.Control.MarshaledInvoke(Control caller, Delegate method, Object[] args, Boolean synchronous)
at System.Windows.Forms.Control.BeginInvoke(Delegate method, Object[] args)
at Microsoft.Reporting.WinForms.ReportViewer.OnRenderingComplete(ProcessThreadResult result, PostRenderArgs data)
at Microsoft.Reporting.WinForms.ProcessThreadArg.OnComplete(ProcessThreadResult result)
at Microsoft.Reporting.WinForms.ProcessingThread.ProcessThreadMain(Object arg)
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.runTryCode(Object userData)
at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart(Object obj)
I was not use threads and I cannot locate cause of error.
Thank you for any help.
|
|
|
|