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Hi.Im a beginner in C# and Im trying to understand the meaning of this function:
public Complex(double r, double i)
{
x = r;
y = i; }
public Complex add(Complex c)
{
x += c.x;
y += c.y;
return this;
}
Anybody can explain me in simple words what is the meaning of this?
Best regards
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These methods are part of a class called Complex. The class seems to hold something like x and y coordinates. The first function is called the constructor for the class. This is where the x and y values are initialized based on the parameters (r, i). The second function is for adding two instances of the class together. So it takes an instance of Comnplex (called c in this case) and adds it to the current instance and returns the new object with the sum of the values.
Ex.
Complex c = new Complex(3, 4);
Complex a = new Complex(1, 2);
a = a.add(c);
Console.WriteLine(a.x + " " + a.y);
Output:
4 6
Does that help?
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This is part of a class or structure called Complex, that handles a complex number[^].
The first method is the constructor of the class/structure. It's called when you create an object of the class/structure. It initializes the variables in the class.
The second method adds two complex numbers.
---
b { font-weight: normal; }
-- modified at 18:02 Saturday 25th March, 2006
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I got a dummy problem while using listbox, combobox or messagebox. When I used these, every thing seems good but, I can't see the messagebox text or listbox or combobox items. I can select the items in the list or combo and get the values or messagebox works well but I can not see the message text itself or the buttons text in the messagebox. Is anyone has ever encountered such problem I know this has a very simple solution but I could not fint it.
Yakup
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hi
i craete image in listview but the image is always in the first place how do i change the location of the image?
my code is:
imageList1.Images.Add((System.Drawing.Image)chart.GetBitmap().Clone())
for ( int i = pam.holdingArrVector.Count ; i > 0 ; i--)
{
lvi = new ListViewItem(new string[3] {" ",Convert.ToString(i-1),pam.CheckNearPivot(i-1)},i-1);
listView1.Items.Insert(0, lvi);
}
when i change listView1.Items.Insert(0, lvi);
to listView1.Items.Insert(1, lvi);
the program is falled
thanks
have a nice day
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This is normal behavior for the listview control. If you want an image in another column you will have to: 1) use a Win32 API trick; 2) make a custom control. Look at Code Project articles for example of custom listview controls. Below is a link using a Win32 API trick.
http://www.codeproject.com/cs/miscctrl/OAKListView.asp
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yosba221 wrote: when i change listView1.Items.Insert(0, lvi);
to listView1.Items.Insert(1, lvi);
The imageIndex parameter is the index of the image in the ImageList, not the column where you want it to appear. Your program is throwing an exception because in the above code you only add one image to the ImageList, and then you are trying to access the second one which is not there.
Luis Alonso Ramos
Intelectix
Chihuahua, Mexico Not much here: My CP Blog!
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I have implemeted a CollectionEditor is my custom control. It now sucessfully serializes and adds my items into the collection. Add/Remove succesully add or remove source code. However is there somthing special that needs to be done in order for VS to clean up the ColledtionEditor item code when the object is deleted by the user?
Thanks.
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Hi all,
I am in a great trouble in drawing shapes. The problem is as follows:
I have a 8bit indexed gray scale image in a picturebox. I want to draw some filled rectangles permanently on the 8-bit image using mousedown and mousemove event of the picturebox. How should I implement this for 8-bit indexed image?
Please help me.
Thanks in advance
Anindya Chatterjee
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Hi. i want to make a searh function in a richTextBox.
Just like in notepad or word ect ect i want a textBox there i could write something and then press searh/find and it searhes trough my text in my richTextBox.
How to do this?
Sorry for my bad english and thx.
Regards
//AeQuitaZ
PS. Thx to Yadav Pramod for the last sulution you gave me. thx.
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If you get all the text in a string without formatting, the string class has a member IndexOf that finds the location of a substring. This[^] override will help you, since you can specify the starting position (probably where your cursor is.)
Luis Alonso Ramos
Intelectix
Chihuahua, Mexico Not much here: My CP Blog!
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I am using a 3rd party component in my code and every time there's a particular error occurs in the execution of the component, instead of passing the error to the code that is running it (the component) the developers decided to just make a Message box show up!!
It totally is inconsistent with my program and since my program runs in a loop, if the particular error occurs, the user gets an endless loop of messageboxes that are really hard to kill. You wind up having to go the task manager to stop my program, because you message boxes from the 3rd party component are "dialog" (or whatever it's called) so you have to click the button and don't have access to my program's window. Very bad programming ethics on their part.
So, I was wondering if there is a way to suppress the messagebox from the 3rd party component? I don't have access to the components source either.
/\ |_ E X E GG
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eggie5 wrote: I was wondering if there is a way to suppress the messagebox from the 3rd party component?
I know this isn't the answer you're looking for, but I would seriously consider dumping the component. However, before I do that, I'd check the documentation for error suppression flags and confirm the message boxes aren't being shown because the component is running in unlicensed (demo) mode.
/ravi
My new year's resolution: 2048 x 1536
Home | Music | Articles | Freeware | Trips
ravib(at)ravib(dot)com
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Yeah, I can't dump it and the docs def. don't say anything about it. They're just lazy.
/\ |_ E X E GG
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As Ravi suggested, I'd throw the component away and find another one (or develop it myself.) If you manage to kill this message box, you don't know if there are more hidden just waiting to pop up with your best customer.
As to how you could kill it, a WH_CBT Windows hook probably would do it.
eggie5 wrote: are "dialog" (or whatever it's called)
It's modal (disables parent window) and modeless (doesn´t disable parent window)
Luis Alonso Ramos
Intelectix
Chihuahua, Mexico Not much here: My CP Blog!
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Asking them devs to fix it would be best but Luis hooking will work or you can remove the message box dialogs completly by debugging the control and noping the calls to the dialog.
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In any case (hooking or patching), there will be problems when a new version is released (most likely with patching.)
Making the developers fix that probably would be hard, altough he can try. If a component-developing company allows that code to be released, I would expect great customer support. Altough I might be wrong.
Luis Alonso Ramos
Intelectix
Chihuahua, Mexico Not much here: My CP Blog!
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Can you explain this "hooking or patching" process to me? I"m not quite sure what you mean...
Also, this component will never be updated again.
/\ |_ E X E GG
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Patching is actually changing the code in the DLL. In you case, suppose you have somthing like this in machine-type pseudocode:
call DoSomething
if error code != 0
go to error
call DoSomethingBecauseNoError
return
error:
call MessageBox("error!!")
returnSuppose you find that code in the DLL and actually modify the file so that the insctruction go to error is changed to a NOP (which is an Intel x86 assembly language instruction that actually does nothing). The next time the DLL is loaded and executed, the DoSomethingBecauseNoError call will always be executed, even if there was a previous error. That's patching: modifying some already-compiled code.
I can also be useful in cracking programs. Suppose you have an app that calls a funcion to check whether it's registered or not. If you patch the beginning of that function (by changing the first instruction for a return true) it will always seem as registered (that's what some cracks actually do.)
Hooks are something totally different. A hook is a way to register your code so it's called before or after some other code, and it can optionally alter the normal behavior. In this case the original code is not modified, but the operating system or the code-to-be-called must provide a way to be hooked.
Windows provides several types of hooks. One of them, the WH_CBT hook, lets your hook procedure be called everytime the system is about to create a window, and you can prevent it from doing so. This way, you could see every window created, and if it's the specific message box, just prevent it.
You can find more information in MSDN:
About Hooks[^]
CBTProc[^]
Your hook procedure must reside in a DLL that will be loaded in the target process, so I seriously recommend it's written in plan Win32 API code. If you write it in .NET, the whole .NET Framework will be loaded in the target process, and there could be a conflict if that process uses another version of .NET.
I hope this helps!
Luis Alonso Ramos
Intelectix
Chihuahua, Mexico Not much here: My CP Blog!
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I don't have any of the source code, all I have is the DLL. Can I still do the patch/hack?
/\ |_ E X E GG
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Yes, that's the idea, without the source code. But it's not easy. You need to disassemble it, find the call to message box, find where you could put a NOP (not all assembly instructions are the same length), get the hexadecimal value of the NOP (it's called the opcode)... it's really not that easy.
I would definitely try to find another component, and if not, I would probably use the hook technique. Patching is the last resort.
Luis Alonso Ramos
Intelectix
Chihuahua, Mexico Not much here: My CP Blog!
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Can you recommend a disassembler to use? I would like to mess around with this.
/\ |_ E X E GG
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You'll have to search for one in google. I've not used one in years. I remember using one called WDASM32, but I don't know if it still exists.
On a side note, I always wanted to write one myself (interesting project) but never did it. Now that I work for a living, I just don't have time.
Luis Alonso Ramos
Intelectix
Chihuahua, Mexico Not much here: My CP Blog!
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can you explain more to me what you mean by
cnich23 wrote: debugging the control and noping the calls to the dialog.
???
Can I do this if I don't have access to the source?
/\ |_ E X E GG
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There is no real easy way to explain this. Either you need to know your machine ASM or if the control is .NET you need to know IL. There are several .NET Dissasmblers some even let you edit the IL code directly. Which in your case you can search for MessageBox and remove them. But there is no easyway to explain this, and most likely it will involve a lot mroe research then waht your trying to accomplish. Best bet is to have the dev's fix it or learn .NET reversing.
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