LabVIEW-ProviderShell

支持 LabVIEW Provider 机制的实现。

1 Class Provider: LabVIEW-ClassProviderShell

This library implements a plugin mechanism for LabVIEW Class. It loads LabVIEW classes from a disk path and converts them to the parent class.

1.1 API

1.1.1 Key API

• LoadLvClasses.vim loads LabVIEW class from a disk path and converts them to the parent class.
  • Path specifies the absolute path to the classes to load. Note: Folders that start with _ or . will be ignored.
  • ClassType specifies the target class type to load. Those classes that are children of the ClassType will be loaded, and the returned classes will be converted to ClassType.
  • milliseconds to wait specifies the time, in milliseconds, that the function waits for loading the classes. The default is -1, indicating to wait until done.
  • error in describes error conditions that occur before this node runs.
  • Loaded Classes returns the loaded classes.
  • error out contains error information.

1.1.2 Utilities

The following utilities provide tools to obtain corresponding LabVIEW class information.

• Get LV Class ParentName.vim
• Get LV Class Version.vim
• Get LV Class Hierarchy.vim
• Get LV Class Description.vim

1.2 Example

The Calculator Example provided by the library demonstrates the plugin mechanism of LabVIEW Class Provider. The math functions of this calculator are loaded dynamically as plugins. Therefore, the calculator has very good scalability.

1.3 Distribution Consideration

This library supports the following forms of code distribution,

1. The shell class is distributed as source code (*.lvclass, *.llb).
2. The shell class is distributed as a packed library (*.lvlibp).

In both situations, the plugin classes can be distributed as source code, packed library, or a mix of both. Notice that the plugin classes must inherit the shell class, whether as source code or as a packed library. In the usual situation, the shell class is often distributed as a packed library (*.lvlibp), so that the shell functions are fixed and uncontaminated. And after the shell is released the plugins can be freely designed by different developers.

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2 VI Provider: LabVIEW-VIProviderShell

Steps

1. 创建实际执行的VI (provider Content VIs), 它们有相同的Connect Pane;
2. 创建 Provider VI, 和实际执行的VI (provider Content VIs)具有相同的 Connect Pane;
3. 拷贝 Template，将所有接线端子放在 Disable Structure 中；
4. *调用方通过 PrepareProviderCall.vi 修改 Provider 实际执行的 VI 路径。

Dependencies

• OpenG Data Library
• OpenG String Library
• OpenG File Library
• OpenG Application Library
• OpenG Error Library