Thoughts on the development of third party Dll,ocx

A question:

Recently there is a job to integrate a set of old fingerprint attendance machine to the present attendance System (Web system), the problem occurs when the old machine only OCX available, no DLL available; originally thought the simple third party call is OK, but OCX can not be carried, in the implementation of the laborious.

B Analysis:

1, the original developer, to provide a set of directly called DLL for Call; (too old, no one, no code, let alone documentation)

2, JavaScript and OCX Interactive, complete the function, (the program changes relatively large, and the site background interactive part of the database access is not very good interaction; also stable phase is not very good)

3, WinForm Bridge; (equivalent to a more pipe effect, the indirect completion of machine interaction)

C Resolution:
Minimum change principle, program stability principle, finally refer to an old system idea (bridging), with the WinForm program to carry out the interaction of the OCX machine, through the socket and the Web program interaction.

The relatively stable phase is still very good.

Taking into account that the machine interaction is not very frequent, and the use of a disconnect request, for each request is a single open socket client communication, complete the timely shutdown. Therefore, to take a separate OCX instance, there is no more open support concurrency problem.

Satisfying the demand is enough. Another count! Ha ha haha

D Summary: (Project accumulation)

1, the document is very important; (developers are reluctant to write documents, but helpless when they actually use the document)

2, the source code is very important, anything that does not understand, you can find the answer in the codes. (Otherwise, you can only decompile, or disassemble.) This is a complete effort.)

3, the demo is very important, a picture is more than words, in the program here is a demo more than words.

Thoughts on the development of third party Dll,ocx