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DDClient Control for Visual Basic

Testimonials from DDClient users

Satisfied users post their recommendations

[On] As a side note, I would highly advise against using VB's built-in support for DDE. I have found it to be very unreliable and unsuitable for industrial applications. I have had very good luck using an ActiveX control from RHA Minisystems to handle DDE. Refer to , which also has an excellent DDE FAQ. (I am not affiliated with RHA Minisystems in any way.)

Brady A. Johnson Software Engineer Click here to see the original

[On] For those of you that need to program DDE beyond the capabilities found in Excel, have a look at this site: There you'll find an advanced DDE client object. I used it in the past for other projects and found it to be faster and more robust than the native DDE support in Excel and VB.

A posting by Peter Cabus. Click here to see the original

Stephen Moseley from Advanced Solutions International wrote-

Our newest product is an ASP (application service provider) for our existing hot selling products: iMIS. iMIS is a vertical market comprehensive software package for not-for-profit associations, and handles everything a not-for-profit association can think of, with the exception of payroll and general ledger (which are not specific to not-for-profit associations). Our oldest product with the most installs uses a software program called Omnis7.

In order to extract data from Omnis7 to upload to our new ASP product, we rely upon DDE. VB is our new development environment, the DDE available from within VB requires a form and works fine, with this one 'show stopper' problem. It will not run with Internet Explorer. So an ActiveX control with DDClient to the rescue. Works like a charm. And we hope that thousands of users across the USA, Canada, Europe & Australia will be using it.

(Please don't use the next paragraph as an encouragement to email for support instead of reading the help file and our support page! - RHA )

Kudos to Roger Abbott for excellent technical support. His replies were always the same day, despite being an ocean apart, and his working day usually over by the time I sent my email. He went above and beyond the call of duty (because most of my problems were being too rushed to read documentation [by the way, I still haven't read the documentation, so this control really is intuitive to integrate into your software], and being too rushed to really investigate what the problems were.)

Walt Whatley from SPARTA, Inc. wrote-

My "product" is a user interface/control software written strictly for internal use. It is the User Interface for machinery used to cure graphite epoxy composite parts. We are using PLCs from control Automation to actually control our machines. They support DDE over a LAN (ethernet). My application allows the operator to input part specific data into the PLC, monitors the status of the process, and logs data to document specifics of the process for each part fabricated.

The DDE support available in VB was completely unacceptable. I need to continuously monitor 32 channels of data from each of 4 machines. This is in addition to periodic reads and writes to another dozen or so memory locations. Since VB only supports synchronous communication on a very limited number of "Hot Links" my app was too slow and very unstable.

Using the asynchronous advise loops in DDClient was the answer. The data updating is blazing fast. I have no trouble constantly monitoring approximately 160 data channels. The poke and request functions allow me the freedom to check on and write to arbitrary channels at will. DDClient was the tool that made my app work.

As to mentioning us on your web site. I am a happy customer, and don't mind your saying so. Since we aren't really in the business of developing software for sale (all my work is address internal needs) putting a link to us on your site doesn't seem to make much sense. A brief description of our success would also be fine with me if you think it would be appropriate.

I'd also like to thank you for your prompt technical support in the past. While I was getting going I had a few problems. You responded quickly with very helpful suggestions.

Thanks again, and keep up the great work.

Walt Whatley

Michele Castiglioni from Techint S.P.A. wrote-

first of all thanks for giving us the registration number for trying out your DDE control. I came back monday at the office and I have replaced all the DDE made with VB text boxes with DDE created in code with an instance of your DDE control. After some tests I can say that the situation is now much better, and we are very interested in the DDE control. Even with the DDE control inserted, however, we are still losing some advise notification from the server ( which is a VB application ). This unique instance of the DDE control is managing a conversation with the server with six advise loops, and sometimes some event is lost for one of these loops ( with another DDE client, written in C++, we don't lose the same event ).

I am wondering if a busy client DDE VB application ( each of this advise loops triggers some data processing ) could lose some of these DDE events, even if the DDE is done with the DDECl OCX ( I am planning to a simpler DDE test VB application to test this )

A couple of days later he wrote again-

after other tests we found that no DDE events is lost. We have therefore decided to buy a single user license of the DDECl control, and we would like to know how to do that. I think the control handles DDE events much better than the standard VB mechanism: the only problem I have found so far is that in some cases the VB IDE crashes when a program is suddenly stopped. This is happening probably because the Uninitialise method of the DDECl isn't called. There is a way to avoid these crashes ?

(There is no way to avoid these IDE crashes. You can read all about it on the support page! - RHA )

In any case thank you for your help in assisting us, only potential customers before today.

Best Regards

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