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DrawImage lets you scale, there's plenty of overloads that take the area to draw into.
Picture boxes are fine if you just want to show a picture quickly, but people tend to try and use them for all sorts of stuff that pushes them beyond what they are for.
Christian Graus - Microsoft MVP - C++
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Ok thanks again, I'll try this out.
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i want to see it, email it to me!
/\ |_ E X E GG
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Hey guys. I'm writing a key schedule method for a cryptographic primitive - the signature of this method is void SetKey(byte[] key). The problem I'm encountering is that I don't know the length of the key array before the method is called, but I need to expand it to a fixed length (say, 256 bits) because all manipulation needs to be done on the fixed-length array.
I won't need this array any more after the SetKey method has finished, and since the array contains sensitive material I'd like it to be wiped from memory as quickly as possible.
I can find four ways to do what I need here:
1. Use something like byte* expanded = stackalloc byte[256 / 8]. The key is declared on the stack, so it will be overwritten on future function calls. Array lookups are also extremely fast, but this code cannot be verified typesafe. The lack of type safety makes it a poor candidate.
2. Create a new array on every execution of the method: byte[] expanded = new byte[256 / 8]. This is typesafe, and I can call Array.Clear before the method returns, but this is dreadfully slow if the SetKey method is called in a loop.
3. Define an array byte[] m_expanded = new byte[256 / 8] in the class containing SetKey. This is typesafe and prevents overworking the garbage collector if SetKey is called in a loop, and I can simply clear the array when the method exits. But putting this temporary array in the class itself seems like bad coding style.
4. For certain primitives, the key needs to be cast to a series of integers, and the key scheduling algorithms operate directly on the integers. I have a structure declared in the class containing SetKey: private struct Block { uint a; uint b; . . . }. Then I can declare Block b; as a local (stack) variable within SetKey and pass ref b as an argument to helper methods (which must operate directly on b). This is typesafe and declared on the stack, so it will be overwritten on future function calls. This only works in cases where the expanded key array is updated in order (index 0, 1, 2, . . ., corresponding to members b.a, b.b, b.c, ...) and where I can unroll the key expanding loop. So this is not a general solution.
Currently I'm using (3) for most of my primitives and (4) for a select few. What I'd really like to do is something similar to (1), but with the ability to make my library typesafe. Is there any method of doing this that I'm missing, or is my current solution the best I can hope for?
Thanks!
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Vega02 wrote: 1. Use something like byte* expanded = stackalloc byte[256 / 8]. The key is declared on the stack, so it will be overwritten on future function calls.
That statement isn't 100% true. It will only be overwritten when enough nested function calls are made such that the stack height overwrites the array. It's possible that the call to SetKey is the deepest call ever made and thus the data is never overwritten.
Jared Parsons
jaredp@beanseed.org
http://jaredparsons.blogspot.com/[^]
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This isn't a big deal as far as I'm concerned. If SetKey is the deepest call ever made, then no encryption or decryption routines have been called, hence no data is protected with this key and the key is useless.
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I need to convert any text entered by a user in a combo box to upper case. So, in the text_changed event, I added the code to convert the text to upper. However, the first time I select the combo box and change the text, it doesn't register the changed text, but the text that was previously present in the combo box (what is loaded into it during the form load event). Is there a reason for this and how do I correct it? Thanks.
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I am creating a round edge panel by inheriting from the panel. What I do is create a graphics path with desired shape and in the Paint method I fill the graphics path and draw the graphics path border with desired color. This would look as if the panel has round edges. So far I have not set the region. Bounds of the panel is still the rectangle.
But the problem come when I set the region of the panel to the Graphics path region. It would not draw the borders( especially left and bottom) properly, it would not draw the curves properly. Also if I set the background image , the image is not smooth along the borders even though I set smoothing mode to AntiAliasing .
Any ideas on why it is behaving this way would be greately appreciated.
Here is the code in Paint method
protected override void OnPaint(System.Windows.Forms.PaintEventArgs e)
{
Graphics gr = e.Graphics;
gr.SmoothingMode = SmoothingMode.AntiAlias;
if(_roundedCorners)
{
// clear background with the parent's backcolor before drawing the round edges
if( Parent.GetType() == typeof(RoundEdgePanel))
gr.Clear( ((RoundEdgePanel)Parent).PanelBackColor);
else
gr.Clear(Parent.BackColor);
gr.DrawPath(_borderPen, _roundedEdge);
// now fill with actual color
gr.FillPath( _graphicsPathBrush,_roundedEdge);
// setting the region of the control
//this.Region = new Region( _roundedEdge); // this is where the problem comes
}
else
{
// set the back color to the color of _graphicsPathBackColor
gr.Clear( _graphcsPathBackColor);
gr.DrawPath(_borderPen, _squaredEdge);
//gr.FillRegion( _graphicsPathBrush, this.Region);
}
}
Thanks,
VpMahank.
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Hi
I am using crystal report to display the report. I am able to do that on my workstation where crystal report is installed.
Now I have to deploy my application on another machine(user machine) which does not have crystal report installed. Is their anyway I can still display report to the user on user machine or I need to install crystal report on user machine first?
Any help would be appreciated.
Thanks
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Crystal_Database_Access2003.msm
Crystal_Database_Access2003_enu.msm
Crystal_Managed2003.msm
Crystal_regwiz2003.msm
Add there Merge modules in setup project and 4th merge module require license you can copy that license from About dialog of MS Visual Studio IDE
Thanks
SANTOSH SATALKAR
Sr. Software Engineer
Sino India GTT Shouguang,
Weifang Area, Shandong PRC,
CHINA.
Ph. 00865365196745
http://www.gtt-sinoindia.com
-- modified at 5:15 Wednesday 4th January, 2006
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I have a public class constructor that reads a file's content. If the file does not exist or the file name/content is wrong, it raises an ArgumentException. I'd like the constructor to return a null object on an exception ie
MyClass mc = new MyClass(string filename);
mc is a valid object if the filename and content is OK, otherwise its null. At present I can create a partially instantiated object, check if a property is null, and fix the problem, but this is inelegant.
Is there a way to do this or am I out to lunch?
Suggestions?
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Out to lunch. You might want to look at the Abstract Factory design pattern [^] to get what you want.
"we must lose precision to make significant statements about complex systems."
-deKorvin on uncertainty
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Hi sjdevo3gsr,
do one thing, simply put your constructor code in try catch Block. Here make sure htat take many catch blocks. like this
try<br />
{<br />
}<br />
catch(ArgumentException argEx)
{<br />
}<br />
catch(Exception ex)
{<br />
}<br />
regards
GV Ramana
-- modified at 14:48 Tuesday 3rd January, 2006
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use the factory pattern for this;
declare a static function that returns this class initialized returning null and use this function instead of new operator.
Mikail Çetinkaya . The C# DEveloper
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In C++, you could overload the new operator, but you can't do anything similar with C#.
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for example in this site :
http://www.google.com/advanced_search?hl=en
how i can choose an option in any of the multiline combo boxes?
like Language, File Format.....
i mean for example in Language i wanna select some language
and in file format i wanna select pdf
thx in advance....
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Hello vedmack,
If one form contains many comboBoxes,
get SelectedValue of each Combobox and do your operations as per the your requirment.
regards
GV Ramana
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i tryed something like this...
HTMLDocument myDoc = new HTMLDocumentClass();
myDoc = (HTMLDocument) axWebBrowser1.Document;
HTMLInputElement combo= (HTMLInputElement) myDoc.getElementById("xxx");
combo.value="Arabic";
combo.click();
but its not working....
any ideas?????
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What I'm trying to do in psuedo code
<br />
foreach( item sourceItem in sourceList)<br />
if (destList.Count == 0)<br />
destList.Add(sourceItem)<br />
else<br />
foreach (item destItem in destList)<br />
if (Conditions(...))<br />
AddAndManipulateExistingItems(...)<br />
else destList.Add(sourceItem)<br />
AddAndManipulateExistingItems() adds 1 or more items to destList and may modify sourceItem and existing items destList. Source list is not kept past this code snippet so modifying it doesn't matter. The algorithm itself is from a vba excel app and is sufficiently complex that I don't want to risk hunting down any side effects burried in several thousand lines of implementation.
My first attempt to do this was done using ArrayLists, but the modifications are breaking the foreach loops and causing InvalidOperationException's. IS there a collection that will let me do this, or will I have to use arrays and resize manually?
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The foreach construct uses an Enumerator to step through the list. If you alter the list, the Enumerator is invalidated. You can loop through the list as long as you don't use an Enumerator, for an example using a regular for loop:
for (int i=0; i<sourceList.Count; i++) { ... }
---
b { font-weight: normal; }
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Thank you. I was sure there had to be a way to do that.
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how can i dial an internet connection using C# when a button is pressed on my form. I have a number of Broadband and Dial Up Connections on Windows XP OS.
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Im really sorry about posting the message thrice. It was an accident.
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