Pass data between 2 applications....

[lidds]

I have 2 stand alone applications in VB.Net, and I want to be able to pass data between both applications e.g.

Senario 1
1) App A will send data to App B
2) App B will then uses this data and write to MS SQL Server

Senario 2
1) App B will send data to App A
2) App A will then use this data.

Both applications need to be able to send and receive data.

I have been looking on the internet and have found a couple of ways of doing this, however I am quite new to the whole VB.Net / programming and I really need some guidance on the most efficient and stable way, and a way that is quite simple to implement (if there is such a process ) )

Could someone please help me in suggesting a way of doing this and possible some guidance with regards to code examples?

Thanks in advance

Simon

 

[Raven65]

Will both applications reside on the same machine, or do you need to also include the ability for passing this data over a network to the individual client machines?

 

[lidds]

No they will both be on the same machine

 

[Raven65]

It's a bit of a "novel" approach, but I have seen this problem met several times simply by writing small data files to a local directory that the other application is watching.

So, ApplicationA may have some information to pass to ApplicationB, it would write this data out to a file in say, ApplicationA\Output\.

ApplicationB would be setup to use a FileSystemWatcher on the folder ApplicationA\Output and when seeing this new file, would act accordingly by opening it, and reading the data.

ApplicationB would of course act in a similar manner to pass info to ApplicationA.

There are more robust approaches available, but I have seen this very simple implementation work on very rapid i/o situations.

 

[lidds]

The developer who is writing App A for me has suggested using windows message, and using a hidden form in both App A and App B to handle the message transfers. This sounds fine to me, and he has said that this is not probably the cleanest way at the moment, however I have a deadline for a presentation so I just need something to work for the moment.

The problem that I have got is that I am unsure of how to implement his suggestion with regards to the coding side of things, I am very new to the window message and coding in general, and I would really appreciate all help.

Below is his email:

Plan to pass data between applications:

Create windows , visible but with no area. X & Y = 1 or 0 . your window will have the title "Simon101" and class name "CLSSIMON101".
In my application my window title will be "Simon202", and a class name of "CLSSIMON202". From this we can search and always find each
window in either application.

Message scheme for data transfer . In each window we will implement a windows standard message WM_COMMAND .
all window massages have an associated WPARAM and a LPARAM. the LOWORD of the WPARAM
will contain sub-messages here are some of those and the values:

_CMD_BEGIN = 1
_CMD_END =2
_CMD_CAMORIGIN =3
_CMD_CAMTARGET =4
_CMD_OBJINDEX =5
_CMD_OBJORIGIN =6

The HIWORD of WPARAM will contain these sub instructions

_CMD_XVALUE =1 -- a float
_CMD_YVALUE= 2 -- a float
_CMD_ZVALUE =3 -- a float
_CMD_LONG =4
_CMD_FLOAT =5
_CMD_INT =6


The LPARAM will contain whatever data not as a pointer, but as static data, I use this method because this will eliminate memory issues..


example 1 message procedure chain
send start message
1- WM_COMMAND, MAKELONG(_CMD_BEGIN,0) , WPARAM(0,0), LPARAM(0)
send origin takes 3 message
2- WM_COMMAND, WPARAM(_CMD_CAMORIGIN,_CMD_XVALUE) , LPARAM(1234.0)
3- WM_COMMAND, WPARAM(_CMD_CAMORIGIN,_CMD_YVALUE) , LPARAM(2344.0)
4- WM_COMMAND, WPARAM(_CMD_CAMORIGIN,_CMD_ZVALUE) , LPARAM(1.0)
send end message
5- WM_COMMAND, MAKELONG(_CMD_END,0) , WPARAM(0,0), LPARAM(0)

example 2 message procedure chain
send start message
1- WM_COMMAND, MAKELONG(_CMD_BEGIN,0) , WPARAM(0,0), LPARAM(0)
send position takes 3 message
2- WM_COMMAND, WPARAM(_CMD_CAMORIGIN,_CMD_XVALUE) , LPARAM(1234.0)
3- WM_COMMAND, WPARAM(_CMD_CAMORIGIN,_CMD_YVALUE) , LPARAM(2344.0)
4- WM_COMMAND, WPARAM(_CMD_CAMORIGIN,_CMD_ZVALUE) , LPARAM(1.0)
send target takes 3 message
5- WM_COMMAND, WPARAM(_CMD_CAMTARGET,_CMD_XVALUE) , LPARAM(2234.0)
6- WM_COMMAND, WPARAM(_CMD_CAMTARGET,_CMD_YVALUE) , LPARAM(3344.0)
7- WM_COMMAND, WPARAM(_CMD_CAMTARGET,_CMD_ZVALUE) , LPARAM(100.0)
send index takes 1 message
8- WM_COMMAND, WPARAM(_CMD_OBJINDEX, _CMD_INT), LPARAM(5062300)
send end message
9- WM_COMMAND, MAKELONG(_CMD_END,0) , WPARAM(0,0), LPARAM(0)

Thanks in advance

Simon