Is possible to include files (linking) based on a component property?
Delphi 2007/2009 odd question here:
It's possible, based on a component property defined in design-time, to include files in linking or leave them ?
Example: If I leave SomeProperty true, when compiling, the unit SomeUnit will be included into my project. Otherwise it will not be included.
My second approach to this problem is to deploy a second component, which when dropped in the form (or not) will include the unit in uses clause. But if it can be done with a property, that'll be better.
I want to avoid conditional compilation via IFDEF because that forces the component to be built every time the projects are built. Or not?
I am trying to achieve an easy way of including some units in project, and then those units will provide support for specific databases. Having these into an option, at the connection component, will be ideally easy: Check support and that's done. Uncheck, and get some less KBs in your compiled APP.
edit: I'll stay with the component way for instance. I knew the IFDEF method and things, but that forces the component to be built everytime the projects are built. Or not?
I was trying to achieve an easy way of including some units in project, and then that units will provide support for specific databases. Having these into an option, at the connection component, will be ideally easy: Check support and that's done. Uncheck, and get some less KBs in your compiled APP.
No.
What are you trying to solve?
You could add a postcompiling step that would optionally include some resource based on a component property - but you'd have to do some coding to implement such a feature.
You can use the {$IFDEF youridentifier} optional code {$ENDIF} method to conditionally compile data in to your application and then to enable it just go to your project options and enter youridentifier into the appropriate option field. Another method of doing this is to add the following to the top of your unit (or in an include file):
{$DEFINE youridentifier}
which will force youridentifier on. To disable, just place a period right before the $:
{.$DEFINE youridentifier}
Using these techniques its easy to conditionally bring in code or replace code with each compile.
Write an IDE add-in. Handle the "before compile" notification and check whether any forms or data modules in the project have components of the type you're interested in, and then check their properties. Based on what you find there, you can try modifying the contents of a unit to use the other unit of your choice. It certainly doesn't sound easy, but it seems possible.
Your second idea is very easy. It's exactly what the TXPManifest component does, for example. Beware that removing such a component from a form does not "unuse" the associated unit.
To conditionally add support for different databases, you might consider using run-time packages. (That's how the IDE manages to support so many different kinds of components, after all.) Put each database's custom code into a different package. Then, the databases you support are simply whichever ones have packages available at run time. No compile-time or design-time configuration required. The obstacle to this, however, is to manage which packages are available, and determine which of them are the packages that provide database support.
链接地址: http://www.djcxy.com/p/67668.html上一篇: 什么是安装组件的最佳方式？
下一篇: 是否可以包含基于组件属性的文件（链接）？