I am using the latest version of the new C++ Mongodb driver/library (not the legacy, 26compat or C version) along with the Qt framework (latest 64b on Linux). Within the same program I am successfully reading and writing to the database and everything is working well.
I realize this version is unstable, but I don't want the boost dependencies and it is a new project, that only I am working on.
I'm not a professional programmer, so please forgive any knowledge gaps.
In my database I have a supporting collection that just remembers the last project a user was working on and I want to do is use a value stored within that document as a string with a field name, to load that project when the program is started.
I am wanting to use the key stored within the m_Current_Project_key variable to load the project data from the project collection.
In the code below the first line after the find statement, carries out the search using different hard coded field name and data in the same collection, just to prove the code works more generally.
The problem I am having is getting the program to search for a specific "_id" that I can see is correctly in the collection and document from the mongo command line.
The comments on the end of the lines of code below show the output achieved for different things I have tried.
This sits within a method that reads a different collection from the same database and get a value from within it, that it puts in the m_Current_Project_key variable which is a QString.
qDebug() << m_Current_Project_key; // "553b976484e4b5167e39b6f1"
qDebug() << Utility::format_key(m_Current_Project_key); // "ObjectId("553b976484e4b5167e39b6f1")" - this utility function just modifies the value passed to it to look like the output
QString test = Utility::format_key(m_Current_Project_key);
test.remove('\"');
qDebug() << test; // "ObjectId(553b976484e4b5167e39b6f1)"
char const *c = m_Current_Project_key.toStdString().c_str();
qDebug() << c; // 553b976484e4b5167e39b6f1
bsoncxx::oid hhh(c, 12);
qDebug() << hhh.get_time_t(); // 892679010
auto cursor = db["project"].find(document{}
// << "title" << "Testing Project"
<< "_id"
<< c
// << hhh
// << m_Current_Project_key.toStdString()
// << m_Current_Project_key.toStdString().c_str()
// << Utility::format_key(m_Current_Project_key).toStdString()
// << test.toStdString()
<< finalize);
The cursor only points to a value when I use the title line above, without the next two lines - the value I get is the document I want, but in the real situation the only thing the program would know, at this point would be the "_id". The project name might not be unique.
I have tried casting the std::string to an OID, but that wasn't recognised as a type.
I've done a lot of Googling and a lot of trying things out and I can't believe there isn't a straight forward way to find a document based on it's "_id". In the examples the only finding examples use values other than the "_id".
db.project.find({ "_id" : ObjectId("553b976484e4b5167e39b6f1")}, { title : 1 })
Does what I want on the Mongo command line.
I would appreciate any assistance I could get with this, I have spent a lot of time trying.
Thanks.
The issue here is that you are using the wrong bsoncxx::oid constructor. When creating an oid from a std::string of the hex representation of the ObjectId (e.g. "553b976484e4b5167e39b6f1") you should use the single-argument constructor that takes a stdx::string_view.
The correct code looks like this:
using bsoncxx::stdx::string_view;
auto cursor = db["project"].find(document{}
<< "_id"
<< bsoncxx::oid{stdx::string_view{m_Current_Project_key.toStdString()}}
<< finalize
);
Background: I want to add my application to the windows context menu, I have done this by adding a new key to the windows registry:
HKEY_CLASSES_ROOT\*\shell\myapp
HKEY_CLASSES_ROOT\*\shell\myapp\command
And assigning the default value of the "command" key to the location of my exe, plus an extra argument:
value = "c:\users\john\myapp\myappexe.exe" "%1" arg1
It works, i can 'right click' any file and run my application with that file. The problem comes when I try to select multiple files, it opens as many windows of my app as files selected, I want to be able to handle all the inputs with one instance of my program.
I'm aware that this may be solved by creating shell extensions as posted here, here, here or here. Creating a full functional shell extension is out of the scope of my (small) project, and I haven't found tutorials which I can understand.
Problem: I'm looking a way around it, and I found that a program called from the "send to" folder in windows is able to handle multiple files, for example, if i put the execulable of this code (c++) in the C:\Users\john\AppData\Roaming\Microsoft\Windows\SendTo folder,
#include <iostream>
using namespace std;
int main(int argc, char* argv[]){
for(int i=0;i<=argc;i++){
cout << argv[i] << endl;
}
return 0;
}
...select a bunch of flies, and drag them into the executable, I'll get in one window the path of all the selected files (send to tutorial). How does this work? Can I use this behavior and apply it to my app?
One approach is to design your application so that any newly launched instance checks for a pre-existing instance (you could use a mutex to do this) and then forwards the command-line parameters to that one, encapsulated in a message of some kind. The original instance can then take the appropriate action.
I have written a DLL function in C++, which I am calling from VBA (Excel).
How can I setup the Visual Studio properties to allow me to debug the function? I have tried specifying Excel, but that doesn’t seem to work.
You have two choices: "direct debug", or "attach".
I strongly prefer the "direct debug" approach for a long list of reasons omitted from here.
There are steps required on both the DLL and Excel/VBA sides, your posting is unclear if all of those steps are addressed.
There are variations on the following:
1) In VS, depending on the version, enter Project Settings, or Project Properties, or equivalent, in the "Debug (not release) Target", go to the Debug or Debugging settings. :
a) There will be an field called "Executable for debugging session", or "command", or something like that depending on VS ver. Here, enter the full path of your Excel exe
b) Optionally, if the same "test spread sheet" is used frequently, enter the full path of your xls (or whatever) in the field called "Command argument", or "program argument" or as in your VS ver.
You may need to surround this with double quotes (e.g. if there are spaces in your path/file names).
c) You can also set the output of your project to a Dir that is "addin helpful", such as a Dir called AddIn (c.f. having the DLL end up in Debug (or Release) Dirs)
... it is assumed that your DLL has all the bits required to export the functions, with the project being of type DLL, plus any DLLEXPORT and compiler directives, etc etc.
... the specifics of the DLLEXPORT settings (and related compiler switches) and Calling Convention will determine many things ... it is assumed you have done all that correctly and consistently (and especially consistently with what the Excel-side is expecting).
... your DLL may or may not have a DLL_Main, if it does, more discussion is required.
2) Before anything else, be sure to have created the Excel-side "interface" for your DLL, ie. the "Add-In". This can be either via .xla, or via .xll. I strongly suggest the .xla route as your first approach.
See the Excel help files etc for creating the .xla
Then, in your XLA's VBA Module(s), declare the functions/subs etc from your DLL. For example, if you have a DLL called Add2_DLL.dll, which contains an exported function "add2_pho_xl", then:
Public Declare Function Add2_Pho_XX Lib "E:\EclipseWorkSpace\Add2_DLL\Debug\Add2_DLL.dll" _
Alias "add2_pho_xl" (A As Double, B As Double) As Double
I have used the Alias approach here, for reasons required below.
In many instances, this declaration can be used directly as User Defined Function (UDF) in your sheets, etc. However, for a vast number of cases, you will need to create a VBA "spinner" function/sub that creates the "ultimate" UDF, and relies on this direct entry function (see below). This is also a very long story, but necessary where more complex matters are required (arrays, variants, etc etc).
NOTICE:
a) the DLL's full path is required unless special steps have been taken. If your Addin is for general distribution ... a much longer discussion is required.
b) the Alias must be the EXACT entry name of the function in your DLL. If you view near the end of the DLL (or .Def) files, and unless you set your DLL modules as Private, those will show the entry names expected on the DLL side.
In this example, the entry name is NOT "decorated" due to the choices in the Calling Convention and compiler switches, but it could look something like
"_add2_pho_xl_#08" etc depending your choices.
... in any case, you must use whatever the DLL has.
3) Once both the .xla and dll exist (it is best if they are in the same Dir), Excel must be "told" about the Add-In. The easiest approach is Excel/Tools/Addins, but there are various strategies for "registering" DLL functions.
4) CRUCIALLY, the argument list properties/declarations MUST BE CONGRUENT with BOTH those in your DLL and the Calling Convention. Three (of many possible) examples of "issues" are,
(i) A Boolean on the VBA-side is two-bytes, if the Bool/Logical on your DLL side is 1-byte, then the Debug will fail, since the two sides "cannot connect" properly.
(ii) Strings ... this can be a very long story. It depends if sent ByVal or ByRef, it depends if the DLL side has "hidden length" Args, etc. etc. Remember, VBA uses COM/OLE VBStrings, which have their own can of worms.
(iii) Variants/Objects: these require a tome onto themselves
5) If ALL (and likely more) of the above have gone well, then in VS set your break points, if required, and "Go" or "Start" the debug (depending on VS ver, etc.). This should launch Excel, and if you also set the target xls, it will launch too. Go to the cell(s) where you addin function (e.g. =add2_pho_XX(A1, B1) ) resides, and execute the cell (sometimes using the "fx" menu item is useful, but there are other ways also).
Some hints:
a) if the func execution crashes/hangs etc Excel and does not even arrive back to the VS side, then likely there is a Arg list conflict (e.g. you are passing a Double to an Int or a million other possibilities), or Calling Convention conflict, etc.
b) In general, you may (while in the VS debug session) simultaneously perform a VBA debug session. That is, after starting the VS bebug, entre the VBA IDE, and set break points in VBA UDF's, if a "spinner" UDF's have been created. For example, a VBA UDF that relies also on the DLL's function.
Private Function Add2_Pho( FirstNum as Double, SecondNum as Double, Optional lMakeRed as Variant) As Variant
'
'
Add2_Pho = Add2_Pho_XX( FirstNum, SecondNum ) ' this is the actual DLL func accessed via Delcare above
'
If( IsMissing(lMakeRed) ) Then
Else
If( cBool(lMakeRed) ) Then
If( Add2_Pho < 0 ) Then
'
' ' make the result Red, or something
'
End If
End If
End If
'
'
End Function
... here, setting a break point at the first line can be helpful to see if the UDF is even entered on the VBA side. If it is, click Continue in VBA, and see if it makes it to the VS side, if not, check Args, Calling Convention, etc again, etc etc
c) If the cell's content are #Value or some other unexpected result, then at least the UDF is "recognised" but not functioning correctly, either due to sheet->VBA issues, or VBA-> DLL issues, or after the return DLL-> VBA
d) Save often! and Use the VBA IDE's Debug/ Compile VBA Project before running anything just make sure VBA internal consistency.
e) Also, if you are using VBA/XLA's, then get a copy of CleanProject (VBA can mess up its internals sometimes, and this Tool will be a life saver)
Please make sure that Debug mode is the active mode.
How to debug your DLL with Excel/VBA
I would like to know how is that the .at() method works, like the one in the Vector class of the C++, a method that both ways returns and/or assign a value to the member of the array.
i don't know if with a macro i can do it, or declaring 2 method with same name... any help?
i have been trying to find and open the file of vector, to see how it was written, that specific method, but i have not found it.
(its for a different structure i am building, but i would like to access to them with only one method)
Example of what i mean.
vec.at(x) = value;
newValue = vec.at(x);
You have to return a reference to the value. So instead of
int at(int idx)
You just do
int& at(int idx)
References are very similar to pointers with the difference that you cannot and dont have to dereference them in order to manipulate the value they are referencing
There should be an easy way to open any source file within the IDE. I use this feature all of the time to review the Standard Library, especially when wanting to review the signature of the member functions of std::vector, std::map, std::list, etc., without having to open a browser window.
Hopefully the IDE used has something similar to "open file at cursor". Since the IDE is not known by the question content, a more generic procedure is presented.
1) Make sure the relevant header name is in a #include line. For example:
#include <vector>
2) Move the editor cursor so that the cursor is clearly shown under a section of the header file name (e.g. vector).
3) Within the IDE run the "open file at cursor" command.
4) The IDE should now show the file highlighted by the cursor in its own window / tab, and there is no need to manually navigate to the area where all header files are located on the development system.
5) Search the newly opened file as desired.
I think this would increase the quality of life when devving, but google came up with nothing and I couldn't find anything specific inside inside Netbeans either.
What I want is to start with this header:
class bla
{
public:
static void gfg(somearg asd);
};
Then I open the blank bla.cpp and pressed 'autoimplement'. After that, it would look like this:
#include "bla.h"
static void bla::gfg(somearg asd)
{
//TODO: implement
throw unimplemented("void bla::gfg(somearg) is unimplemented");
}
Anyone know of a tool like this?
I found http://www.radwin.org/michael/projects/stubgen/
"stubgen is a C++ development tool that keeps code files in sync with their associated headers. When it finds a member function declaration in a header file that doesn't have a corresponding implementation, it creates an empty skeleton with descriptive comment headers."
This looks like it does exactly what you want it to do.
Some time has passed and in the meantime the requested feature seems to have been implemented in netbeans. Refer to https://netbeans.org/bugzilla/show_bug.cgi?id=213811 , which also gives a description on how to use it:
Note:
Implemented CTRL+SPACE.
IDE suggest implementing of class method if CTRL+SPACE was pressed:
- inside file that already has at least one method definition
- between method declarations