Advanced coding with DLL

ingvar_e · #1 (**permalink**) 01-17-2009, 09:41 PM

I am trying to create a DLL library with Microsoft Visual Basic 6.

I have written DLL:s for other applications than MT4 with VB6. The problem is that you get forced into a structure that demands that you call the DLL in this fashion (in VB):

Dim someObj
Set someObj = CreateObject("someDLL.SomeCodeModule")
someObj.SomeFunction parm1 parm2.....

As far as I figure this kind of setup is not possible in Metatrader.

I have tried lots of variation to code the DLL inVB6 to allow the simpler calling method that can be used in MT4 but not succeeded.

Anyone done this?

Ingvar

wolfe · #2 (**permalink**) 01-17-2009, 10:32 PM

What do you want your dll to accomplish?

ingvar_e · #3 (**permalink**) 01-17-2009, 11:07 PM

The DLL will act as an intermediate between MT4 and an Excel spreadsheet both delivering data to the spreadsheet and collect data. I have no problem communicating with the spreadsheet. Its communicating with MT4 that is the problem. The structure of the EA:s I have built have all required the calling structure described and that is not suitable for MT4 it seems.

wolfe · #4 (**permalink**) 01-18-2009, 03:55 AM

Quote:

Originally Posted by ingvar_e

The DLL will act as an intermediate between MT4 and an Excel spreadsheet both delivering data to the spreadsheet and collect data. I have no problem communicating with the spreadsheet. Its communicating with MT4 that is the problem. The structure of the EA:s I have built have all required the calling structure described and that is not suitable for MT4 it seems.

You may be having a string problem. Are you having mt4 read a double value such as a price quote from Excel? If Excel is returning a string, you may need to convert this to a double in mt4. Not sure if that is your problem or not.

I only have experience reading and writing to .txt or .csv files. Often you have the need to convert a string value to a double or integer for mt4 to make sense of your values.

Some of these mq4 functions may be helpful:

StrToDouble( string value)
StrToInteger( string value)
StrToTime( string value)

Not sure if this is helpful to you or not.

StooperTwada · #5 (**permalink**) 01-18-2009, 04:57 AM

@ingvar_e; you said...

Quote:

I have written DLL:s for other applications than MT4 with VB6....

Have you ever tried an excel interface for Saxo Trader dll's or know anyone who has attempted this? I would be interested in getting a feed similar to the excel command/formula in MT4 for saxo trader e.g. =(MT4|BID!GBPUSD) for the currency pairs they provide plus an interface to place trades on the trade board via excel.

If you know of a past thread etc, I would be very interested in any information you may have as I have all my trade analysis/alerts and back test macros for end of day info that I fat finger in and would like to go to intraday time frames.

And please excuse me for asking this is a MetaTrader thread. I have been searching for this for a while.....

StooperTwada · #6 (**permalink**) 01-18-2009, 06:49 AM

Sorry - for some reason I do not have edit rights to delete my above response. I hereby withdraw the above request on the grounds that it is in breach of the customer agreement.

I am now highly considering closing my account with Saxo....

ingvar_e · #7 (**permalink**) 01-18-2009, 08:22 AM

Wolfe wrote:
>You may be having a string problem

No, It is a problem even to get in contact with the DLL since the DLL require you to instanciate the DLL (See sample code for calling the DLL from VB).

I have to rephrase one of my sentences.

The structure of the DLL:s I have built have all required the calling structure described and that is not suitable for MT4 it seems

Ingvar

wolfe · #8 (**permalink**) 01-18-2009, 07:23 PM

Example code of .ccp:

PHP Code:


			
// Your_dll.cpp : Defines the initialization routines for the DLL.
//

#include "stdafx.h"
#include "Your_dll.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

#define MT4_EXPFUNC __declspec(dllexport)


// CYour_dllApp

BEGIN_MESSAGE_MAP(CYour_dllApp, CWinApp)
    //{{AFX_MSG_MAP(CYour_dllApp)
        // NOTE - the ClassWizard will add and remove mapping macros here.
        //    DO NOT EDIT what you see in these blocks of generated code!
    //}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CYour_dllApp construction

CYour_dllApp::CYour_dllApp()
{
    // TODO: add construction code here,
    // Place all significant initialization in InitInstance
}

/////////////////////////////////////////////////////////////////////////////
// The one and only CYour_dllApp object

CYour_dllApp theApp;

MT4_EXPFUNC void __stdcall Your_Function()
{
 // Your Function code here
 // 
}

Make sure you declare your export function in the .def file:

PHP Code:


			
; Your_dll.def : Declares the module parameters for the DLL.

LIBRARY      "Your_dll"
DESCRIPTION  'Your_dll Windows Dynamic Link Library'

EXPORTS
    ; Explicit exports can go here

    Your_Function

Make sure to copy your release dll project to C:\WINDOWS\system32. Mt4 can access your dll there.

ingvar_e · #9 (**permalink**) 01-18-2009, 07:43 PM

Thanks Wolfe.

You have to forgive me ignorance. I do not really know what to do with code samples you provided. PHP? Not familiar with PHP at all. Looks more like C yo me.

Like the pupil said after having got a second explanation.

"I am still confused but at a substantial higher level"

wolfe · #10 (**permalink**) 01-19-2009, 02:47 AM

Quote:

Originally Posted by ingvar_e

Thanks Wolfe.

You have to forgive me ignorance. I do not really know what to do with code samples you provided. PHP? Not familiar with PHP at all. Looks more like C yo me.

Like the pupil said after having got a second explanation.

"I am still confused but at a substantial higher level"

Sorry, it's not Visual Basic. The examples are in visual C++ 6.0.

Mt4 dll's will work when coded in C++.