managed c++.net: allocating the memory for an array of struct in a coherent memory area - .NET (Core and Framework) Discussion Boards

Dear Christian,
I am not getting reply for these queries. Please tell me if you know this please. Even tell me if know it for Windows only. Give me some code snippet or links if possible please.

can any body tell me the code for customizing the crystal reports as per the given format in either windows form or in web application.
Letus suppose my client has few papers in already printed format. "Company Name : " in that empty place "Akebono Soft" must be printed. In this way the crystal report should print the content in specified way only.
First of all can I do it. If so, how can I do it. Thank you.

Regards,

S/W Engineer
Akebono Soft Technologies
aleem_abdul@akebonosoft.com.

I'm planning to extend a large .NET project (3 solutions / 20 projects) to Unix through Mono (there should be separate autorun installers for Windows, Linux and Mac OS on a CD for end user).

There are many problems. The big one is the use of platform-specific features (registry, API calls) and the other that it is all made with VS 2003 IDE.

I know there is not any universal answer for this, but any help or links to information resources would be appreciated - thanks a lot.

Hi all

I have an app that hosts the IE AxWebBrowser control. I would like to have the app automatically resize for each loaded page to the smallest width (within reason) that can display the page without a horizontal scoll bar appearing. It would be great if this was a simple calculation but in the worst case it is also acceptable for me for that value to be determined theough multiple tests (i.e. best would be some magic "int RequiredWidth()" method, but acceptable would be a "bool HasHorizontalScrollbar()" method that I can use to converge on the optimal width.

Does anyone know how I can implement either of these two?

Thanks!

Hi all,
can any body tell me the code for customizing the crystal reports as per the given format in either windows form or in web application.
Letus suppose my client has few papers in already printed format. "Company Name : " in that empty place "Akebono Soft" must be printed. In this way the crystal report should print the content in specified way only.
First of all can I do it. If so, how can I do it. Thank you.

Regards,

S/W Engineer
Akebono Soft Technologies
aleem_abdul@akebonosoft.com.

Hi,

I am considering various obfuscators and protection systems and am considering .Net Reactor in view of it's performance and price.

If anyone has any recommendations/comments, I would appreciate the feedback.

Thanks.

Glen Harvy

Glen Harvy

is there any possibility in the 2.0 Framework to have a preview of a webcam and to record the stream to disk

You need to download and install the Platform SDK, which includes the DirectShow library. It has samples of this sort of stuff ( in fact, tehre are also samples on the site itself )

Christian Graus - C++ MVP

'Why don't we jump on a fad that hasn't already been widely discredited ?' - Dilbert

Hi,

first of all, plz excuse my rusty english Wink | ;)

I'm writing a little wrapper in c++ .net which allows me to access some old unmanaged win32 c++ dlls from a c# program.

There is one function in the dll which drives my crazy.

It wants an array of struct as an argument, called by reference.

Its code is looking like that (a bit simplified):
the struct in c++.net and in the dll code:

<br />
struct ParaList<br />
{<br />
  BYTE adress;<br />
  WORD length;<br />
};<br />

the dll function prototype (in the dll -> non c++.net):

<br />
BOOL RequestValues(ParaList list[], int listlength);<br />

I included it into my c++ .net like following code:

<br />
[DllImport("mydll.dll",EntryPoint="_RequestValues@12")]<br />
extern "C" bool_cdecl RequestValues(ParaList *list, int listlength); <br />

What it does is: I can request the values of some parameters by executing the RequestValues() function.
After that I can read the requested values by executing a readfunction().

I'm calling the function in managed c++.net like that:

<br />
ParaList list[8];<br />
list[0].adress = 0x1;<br />
list[0].length = 0x1;<br />
bool error = RequestValues(list, 1); //querying for one parameter value<br />

The problem now is: when the list only has one parameter (like in the example above) the function works correct. But when I request more than one parameter, the dll will put out some error.

In a c++ mfc example the dll is working correct!

I think the problem is related in the memory management of c++.net.
I'm pretty new to c++.net. Am I right that in managed c++.net the allocated memory for an array must not be in sequence? So the single elements of the array are distributed all over the memory?
In that case the dll would get only the pointer on the first array element but the second element is not the neighbour, so the dll reads garbage when it wants to read the data of the second array element.

I tried a few things with __pin and __nogc keywords which led to nothing Frown | :(

Does anyone have a clue how I can tell c++.net to allocate the memory for the array in a coherent memory area?

Thanks for reading this!
~Sepp

It's easier to use pinvoke to call functions from c++ dlls.

There is a C++/CLI forum, if you ask there, Nish is bound to find it and help you.

Christian Graus - C++ MVP

'Why don't we jump on a fad that hasn't already been widely discredited ?' - Dilbert

Hi,
thank you for your reply!
Finally I found the problem by my own.

The problem was the structure:

<br />
struct TMP<br />
{<br />
   DWORD x;<br />
   WORD  z;<br />
};<br />

A sizeof(TMP) told me that it's 8 Bytes big.
The strange thing here is that a DWORD is 4 Bytes and a WORD is 2 Bytes big (confirmed by sizeof(DWORD) and sizeof(WORD). If you count it together it's 6 and not 8???

The DLL function expected an array of 6 Bytes structs.
What it got was an array of 8 Bytes structs, which led to that the Dll got garbage while it was reading the second array element.

What I did now, was splitting up the DWORD into two WORD variables:

<br />
struct TMP2<br />
{<br />
   WORD x1;<br />
   WORD x2;<br />
   WORD z;<br />
};<br />

sizeof(TMP2) says that it's 6 Bytes big now. Really strange.

There is nothing really strange about that, C (and C++ I guess) pads all its structs
so all elements are "naturally aligned" (to an adr that is a multiple of their size),
and aligns the entire struct to the size of the largest element, in your case 4B due to the DWORD/int.
The reason is the compiler can then emit code that manipulates 4B quantities without worrying
about alignment and/or achieving highest performance. (Some processors do not know how to
load a DWORD from an unaligned adr, others do but take more time to do it).

The net result is:

1)
if your struct's size is not a multiple of 4 but contains elements sized 4B, the struct will
act as if its size is a multiple of 4B (even when sizeof shows otherwise).

2)
if the elements in your struct are not "naturally aligned", the struct will be padded with
extra bytes to achieve the natural alignment (=each element gets aligned according to its size).
So
struct {
byte a; // offset 0
short b; // 1 ? not naturally aligned
byte c; // 3 ? OK
byte d; // 4 ? OK
long e; // 5 ? not naturally aligned
}

gets compiled as if it were:
struct {
byte a; // offset 0
byte bDummy;
short b; // offset 2
byte c; // offset 4
byte d; // offset 5
byte eDummy1;
byte eDummy2;
long e; // offset 8
}

The function you used was an old one, relying on a stride of 6B, so something special needed
to be done. In C (and C++ I guess) there are compiler switches and/or pragmas to disable
the alignment/padding. In C# your splitting the 4B into two 2B elements is probably the
best way to get what you needed.

Smile | :)

Luc Pattyn

Hi ~

For the databinding for the control class

i.e. Control.DataBindings.Add(string propertyName,object dataSource,string dataMember)

for the parameter of dataSource and dataMember, how can i bind the value of the control to the specific in array

e.g. if i have a class

public class Person{
public object[] extras

}

then i want to bind the control with the second element in Person.extras i.e. Person.extras[1]

i try the following ways, but not success

controlObj.DataBindings.Add("Text, person.extras, new object[] {1});

and

controlObj.DataBindings.Add("Text", person, "extras[1]");

Thank Smile | :)

The Control i need to being binding to is allow to bind the single value only, such as TextBox, can just bind to a sigle value. But ListBox can bind to a list or array because it allow multiple to display in the control

Hi All,

My task is should create Sharing a folder using web application in .net.

The Sharing folder (and its files) shold be visible to all in network.

I have searched a lot,to get an article,but failed to succeed.

Plz suggest me or else provide a good article as iam new to creating web applications in .net

Thx in advance

Nagaraju

I heard a collegue of mine mention this, but uncertain of its truth...

 software built with Microsoft's .Net (and later) compilers <br />
creates executables in a "common format" that can be run through<br />
commercially-available disassemblers to fully recover the original<br />
source code. the protection against this is to use scramblers.

Can anyone veryify this?
Thanks,
Johnny

Simplistically, code written against .NET is compiled into IL (intermediate language). This IL can be reversed back into source code. Obfuscators can be used to make this reversing much more complicated.

Now, it is important to note that no source code (in any language) is 100% safe from reverse-engineering. Given the time/motivation you can reverse any source.

the last thing I want to see is some pasty-faced geek with skin so pale that it's almost translucent trying to bump parts with a partner - John Simmons / outlaw programmer

Deja View - the feeling that you've seen this post before.

Follow up question: is it (now) easier to reverse engineer code compiled in .NET?

From unprotected code, yes.

the last thing I want to see is some pasty-faced geek with skin so pale that it's almost translucent trying to bump parts with a partner - John Simmons / outlaw programmer

Deja View - the feeling that you've seen this post before.

Thanks all! I can sleep better tonight Smile | :)

It's close to the truth, but it's not truth.

software built with Microsoft's .Net (and later) compilers
creates executables in a "common format" that can be run through
commercially-available disassemblers to fully recover the original
source code.

False.

The original source code can not be recovered as it's not included in the compiled code.

Reverse engineering can recreate code that will do the same thing as the original code and will compile into an identical executable, but the recreated code will not be the same as the original source code.

the protection against this is to use scramblers.

False.

Scramblers provide some level of protection, but it's impossible to completely protect any code from reverse engineering.

---
Year happy = new Year(2007);

Hi every body,
Can I customize the paper size and print a crystal report directly by coding. And my client have some printed papers, he needs to print the data at required places only. Like "Name : Code Project" here Name : is laready printed and it has to print CodeProject at specified place exactly.
How can we do it please advice me.Thank you.

Regards,

S/W Engineer
Akebono Soft Technologies
aleem_abdul@akebonosoft.com.

I created a C# appln using .Net 1.1v framework, which is tested on a system having .Net 2.0v framework installed. Application is opening and working fine. But some places, application is throwing messages "Object reference not set to an instance of an object." and continues to work. But these messages no where appeared on my system which is having only .Net 1.1 framework. But when I install .Net 1.1v framework on the test machine, application is taking the 1.1 framework and working fine for the previous test case. Why some classes of .Net 2.0 are not working with 1.1v framework created application assembly. Is .Net2.0 is backward compatible with .Net1.1???

Thanks in advance...

Regards,
Sunil Jampa.

Sunil Jampa wrote:
Is .Net2.0 is backward compatible with .Net1.1???

I guess you've found that the answer is 'no'. In fact, you can mark your app to require the exact version that was used to build it. I'd have said that overall I'd not expect a problem, you should try to work out the issue, just in case it needs resolving either way.

Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog

This In General, we do like this only. We will work and create appln on .Net1.1, and later point of time, users can install .Net2.0 or .Net3.0 or some future release...We cannot pinpoint each piece of code again and again and do some work around for each framework. .Net framework itself should take care about this issue. But it is not doing.

Any body can please comment on this statement ".Net 2.0 is not backward compatible with .Net 1.1".

Regards,
Sunil Jampa.

Well, you can either track down the issue and understand it, or you can trawl online forums, hoping someone will make a statement that makes you feel better about the issue you are having. I've never had issues moving from 1.1 to 2.0, and I've moved at least one large project over.

Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog