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I have basic knowledge of C and C++(basically can read the code to understand what its doing and basically write a small utility here and there in C or C++). However for the last couple of days I am trying to research on the API's. I have seen examples being used in Visual Basic and haven't been able to come across a good sample or document as to how I could use the API in C++ or I might have just not understood it.
I personally would prefer doing a project in VB however am being told I will reach my limitations with VB within hours and am better off with either using C or C++.
Here are the API's I am trying to find examples with or any articles to try and understand with examples would be a great start. I just don't want to start and have to ask questions every hour...
The main API's I am intrested in are :
If I can I will explain this from some of the documents and the usage I have seen in VB.
A) WindowFromPoint(X, Y)...This has to be the point I am looking for on my desktop and it could end up being an external window or my own window at that location. Obviously no point to point it to my own window.
For usage in C++ I would be storing the return valuse in a long variable or do I have to declare my variable as a HANDLE?
C++ usage
1) HANDLE h = WindowFromPoint(499,15)
OR use as
2) Long h
h = WindowFromPoint(499,15)
////
B) GETDC(h) This is getting the device context from using the handle we just passed. However what is the return value for this...VB example states its long?
1) Long h
hd = GetDC(h)
C) BitBlt (Destination picture object's.hdc, a RECTANGLE BLOCK, hd we got from B above, nect two parameter 499, 15 used in the WindowFromPoint, COPY)
Please am I on the right track with this 3 API's.
Thanks a million.
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WindowFromPoint[^] has the following prototype:
HWND WindowFromPoint(POINT Point);
As can be seen, the return type is HWND, not HANDLE. Also, it takes a POINT point structure, not two numbers. Try something like this:
HWND h = WindowFromPoint(POINT(499,15));
Steve
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Thanks Steve for your reply.
However I haven't started coding this yet...I am still looking for documentation or something to refer to before I start coding.
However you could help me if you can by answering a couple of questions...the 3 Api's in VB examples and other documentation I have seen been used in VB. Am I right in saying If I create a Picture control in my application and having passed the correct parameters to the 3 API's, I should be able to get a portion of the desktop in that picture button?
Or is there a better way...All I am trying to do is from point 499,15 I need that section in a picture control of size height 615 and width of 375.
I guess it is doable all I have to do is make sure I pass the right parameters?
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FISH786 wrote: I should be able to get a portion of the desktop in that picture button?
What do you mean by "get a portion"?
Steve
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Like the source window is 800 X 600 however i only want a rectangular block of 17 X 22 from point 499,15. Into my application.
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What, you mean you want to do a screen capture of a portion of the picture control?
Steve
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No Screen Capture of a portion of a window into a Picture control.
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Hi,
I am wanted to convert/store a string, which has XML elements, into a dataset or data table. The string that I am reading from a service is the result of my query. I have written the following code,
{
DataSet ds = new DataSet();
StringReader stream = new StringReader(xmlString);
ds.ReadXml(stream);
DataTable dt = ds.Tables[0];
dg.DataSource = dt;
return dt;
}
I am receiving two different type of strings, they are
xmlString1:
<?xml version="1.0" encoding="UTF-8"?>
<nh:rows xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:nh="http://nhdb">
<nh:urnumber>0123456</nh:urnumber>
<nh:surname>xxxxx</nh:surname>
<nh:forename>yyy</nh:forename>
<nh:middlename></nh:middlename>
<nh:dob>1958-10-05</nh:dob>
<nh:address>Mxaxixlx</nh:address>
<nh:suburb>Prxxxx</nh:suburb>
<nh:state>Vxxx</nh:state>
<nh:postcode>3072</nh:postcode>
<nh:patientphone>phone</nh:patientphone>
<nh:gender>Female</nh:gender>
<nh:unit>Sxxxxx Oxxxx</nh:unit>
<nh:ward>Bxxx DPxx</nh:ward>
</nh:rows>
xmlString2:
<?xml version="1.0" encoding="UTF-8"?>
<nh:rows xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:nh="http://nhdb">
<nh:urnumber>0123450</nh:urnumber>
<nh:surname>Cxxxxxx</nh:surname>
<nh:forename>RxxxxxT</nh:forename>
<nh:middlename></nh:middlename>
<nh:dob>1954-07-19</nh:dob>
<nh:address>'ANNANDALE'</nh:address>
<nh:suburb></nh:suburb>
<nh:state></nh:state>
<nh:postcode></nh:postcode>
<nh:patientphone></nh:patientphone>
<nh:gender>Male</nh:gender>
<nh:unit></nh:unit>
<nh:ward></nh:ward>
<nh:urnumber>0123451</nh:urnumber>
<nh:surname>KROL</nh:surname>
<nh:forename>ANILLA</nh:forename>
<nh:middlename></nh:middlename>
<nh:dob>1958-12-10</nh:dob>
<nh:address>68A CLARENCE</nh:address>
<nh:suburb></nh:suburb>
<nh:state></nh:state>
<nh:postcode></nh:postcode>
<nh:patientphone></nh:patientphone>
<nh:gender>Female</nh:gender>
<nh:unit></nh:unit>
<nh:ward></nh:ward>
<nh:urnumber>0123452</nh:urnumber>
<nh:surname>GEYER</nh:surname>
<nh:forename>MAUREEN</nh:forename>
<nh:middlename></nh:middlename>
<nh:dob>1948-06-02</nh:dob>
<nh:address>19 JAYSON</nh:address>
<nh:suburb></nh:suburb>
<nh:state></nh:state>
<nh:postcode></nh:postcode>
<nh:patientphone></nh:patientphone>
<nh:gender>Female</nh:gender>
<nh:unit></nh:unit>
<nh:ward></nh:ward>
</nh:rows>
The above code works perfectly for the xmlString1 and it is converting a data table with single row of data for the cloumns urnumber, surname, forename, middlename, dob, address, suburb,state, postcode,patientPhone, gender, unit, ward.
When I am receiving the xmlString2, the data table is populated with only one column urnumber_Text(for all ur numbers in the xml string).
What am I missing here? Is there any other genuine way of doing it?
Thanks a Lot for your valuable time and invaluable advice.
Looking for advice,
Renu
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I'm using HttpSendRequest to POST data to a secure web page. Will the function automatically re-post the data if a reply isn't received in a certain time? The author of the destination web page claims they are receiving the post twice (30 seconds apart) but I'm 99.9% sure there is only one call to HttpSendRequest from my application. If the reply is received in a few seconds there's no problem.
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Hi,
I recently started my first project based around DLLs and have run into a little trouble.
I followed this tutorial: http://www.codeguru.com/cpp/cpp/cpp_mfc/tutorials/article.php/c9855
The code is split up into a header file and a source file.
It consists of a namespace, which contains variables and a class.
I am linking implicitly.
In a test program I can access the variables fine, no problems there, but when I use a function from the class, I get linker errors, eg:
<pre>1>ELQTest.obj : error LNK2019: unresolved external symbol "public: static bool __cdecl ELQ::Functions::CreateRot(void)" (?CreateRot@Functions@ELQ@@SA_NXZ) referenced in function _SDL_main</pre>
Now for some code:
DLL Header:
#ifndef _ELQDLL_H_
#define _ELQDLL_H_
#include <SDL.h>
#include <cmath>
#include <windows.h>
#pragma comment(lib, "SDL.lib")
#pragma comment(lib, "SDLmain.lib")
#if defined DLL_EXPORT
#define DECLDIR __declspec(dllexport)
#else
#define DECLDIR __declspec(dllimport)
#endif
namespace ELQ{
extern "C"{
#pragma data_seg (".globals")
DECLDIR bool keyboard[27], open;
DECLDIR double sins[720], coss[720], v, posx, posy, posz, f, h;
DECLDIR int WIDTH, HEIGHT, DEPTH, BPP, q, speed, theta, *map, o, lx1, ly1, lx2, ly2, lx3, ly3;
class Functions{
public:
static bool CreateRot();
};
}
}
#endif
DLL Source:
#include "ELQDLL.h"
#define DLL_EXPORT
#if defined DLL_EXPORT
#define DECLDIR __declspec(dllexport)
#else
#define DECLDIR __declspec(dllimport)
#endif
namespace ELQ{
extern "C"{
#pragma data_seg (".globals")
DECLDIR bool keyboard[27], open = false;
DECLDIR double sins[720], coss[720], v, posx, posy, posz, f = 10, h;
DECLDIR int WIDTH, HEIGHT = 10, DEPTH, BPP, q, speed, theta, *map = NULL, o, lx1, ly1, lx2, ly2, lx3, ly3;
DECLDIR bool CreateRot(){
for(int x = 0; x < 720; x++){
sins[x] = sin((x-360)*0.017);
}
}
}
#include "stdafx.h"
#include "ELQDLL.h"
#include <iostream>
SDL_Surface *screen;
int main(int argc, char *argv[]){
if(ELQ::Functions::CreateRot())
system("PAUSE");
return 0;
}
Any idea what could be wrong?
I've played around with all sorts of combinations of class definitions, export/import symbols etc, yet cannot get this to work.
Look forward to your input,
Thanks,
Nat.
PS: Oh, I should say that when I compile the DLL, I get a stream of inconsistency messages, could this be related?
"Sir, I protest. I am NOT a merry man!"
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Those extern "C" statements look wrong - especially as a) you're using namespaces and b) you're enclosing class definitions in them. Now, namespaces and classes are C++ features - they really aren't compatible with extern "C", which specifies that the names enclosed by the extern "C" are exported as undecorated, C names rather than decorated C++ names.
BTW - a decorated C++ name is something like ?CreateRot@Functions@ELQ@@SA_NXZ, your missing symbol...
So - try removing all extern "C" things. The only reason for extern "C" is to export functions compiled with a C++ compiler in a form compatible with C. You're exporting namespaced functions and classes - they will never be compatible with C...
Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p
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Thank you very much!
I feel like a total fool now, though. Classes in C?! They should revoke my C++ licence for that. 
"Sir, I protest. I am NOT a merry man!"
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Don't sweat it man - we've all done it one time or another!
Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p
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See I have a SDI app with a (e.g.) CEditView drieved view. Now I want to create another view of my document, drived from (e.g.) CRichEditView. I dislike the user to have a splitter window at the execute time, but when pressing a menu item. can I use CFrameWnd::CreateView? how if yes?
Thank you masters!
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Do you want to display both views at once (in which case having a splitter is really the best idea) or one view at a time?
Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p
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Yes, both at once
Thank you masters!
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Since CRichEditView is derived from CView you must use CRichEditView::Create (Actually CWnd::Create) and then use CDocument::AddView. CFrameWnd::CreateView is for views that are not derived from CView.
«_Superman_»
I love work. It gives me something to do between weekends.
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class Employee {
public:
Employee(string name = "No Name",
string id = "000-00-0000",
double salary = 0)
: _name(name), _id(id)
{
_salary = salary;
}
...
};
I'm not sure what the [ : _name(name), _id(id) ] does. Can anyone please explain?
Thanks
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They're initializer shortcuts for your member variables. Those statements are the same as saying
_name = name;
_id = id; immediately within your constructor body.
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Quick follow up:
: _name(name), _id = id
{
_salary = salary;
}
Shouldn't I be able to do this?
Thanks
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That's not allowed, see, for instance [^].
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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No, but you can do this.
: _name(name)
{
_id = id;
_salary = salary;
}
The difference is that _name(name) is initialization and _id = id is assignment.
This is equivalent to
type _name = name; and
type _id;
_id = id;
«_Superman_»
I love work. It gives me something to do between weekends.
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Hello su_penguine,
Its called constructor initializer list. Check this[^] and this[^] for more information.
Regards,
Jijo.
_____________________________________________________
http://weseetips.com[ ^] Visual C++ tips and tricks. Updated daily.
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Does anyone know why Skype seems incompatible with Vista Home edition?
Sorry its not a C++ question. But you guys are the best.
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Ric Ashton wrote: Does anyone know why Skype seems incompatible with Vista Home edition?
Because your question is incompatible with this forum. 
Better place to ask :Here[^]
He never answers anyone who replies to him. I've taken to calling him a retard, which is not fair to retards everywhere.-Christian Graus
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