XControl: Difference between revisions
Reorganized page and added more detail. |
|||
| Line 1: | Line 1: | ||
'''XControls''' were first introduced in [[LabVIEW 8]] and enhance the power of front panel objects. An XControl is a front panel object with dedicated UI logic code linked and encapsulatedin the XControl in order to react to user events on the controls in contains. An XControl consists of several parts, managed in a ''.xctl'' file. The ''.xctl'' file is a XML-file like the project-file or [[Library]] files. Other parts of the XControl are called: | |||
*[[XControl:Properties|Properties]] | |||
*[[XControl:Abilities|Abilities]] | |||
*[[XControl:Methods|Methods]] | |||
XControls | |||
__TOC__ | |||
== Limitations == | == Limitations == | ||
An XControl functions like a subpanel in the hosting VI. Subpanels (and therefore XControls) ''can not'' be placed inside an array. Note that you ''can'' define your XControl data as an array of any LabVIEW data type, and you ''can'' use array controls in the facade vi. | An XControl functions like a subpanel in the hosting VI. Subpanels (and therefore XControls) ''can not'' be placed inside an array. Note that you ''can'' define your XControl data as an array of any LabVIEW data type, and you ''can'' use array controls in the facade vi. | ||
Using LabVIEW native objects (.lvclass files) inside the state control of an XControl tends to crash LabVIEW for versions less than 8.5.1 when the XControl is used in a different application instance. | Using LabVIEW native objects (.lvclass files) inside the state control of an XControl tends to crash LabVIEW for versions less than 8.5.1 when the XControl is used in a different application instance. | ||
Also, XControls have limitations when running in VIs that are part of a [[Library]] (or [[Packed Project Library|Packed Project Library (PPL)]]), or a [[LabVIEW Class]]. This makes it difficult to use in a large application using [[Actor Framework]] or plugin architectures using [[Packed Project Library|PPLs]]. See more in the [[QControl|QControls]] article. | |||
== Tricks == | == Tricks == | ||
*If you require a variable number of runtime instances of your XControl, Jarrod Slocum of [[National Instruments]] has created an example [http://community.ni.com/examples/linked-object-list-in-labview-8-0-using-xcontrols Linked Object List] based on a Subpanel ''inside'' an XControl. | *If you require a variable number of runtime instances of your XControl, Jarrod Slocum of [[National Instruments]] has created an example [http://community.ni.com/examples/linked-object-list-in-labview-8-0-using-xcontrols Linked Object List] based on a Subpanel ''inside'' an XControl. | ||
*If you want to react to dynamic events (or user events) you need them to register at the XControl Facade '''before''' the event happens. | * If you want to react to dynamic events (or user events) you need them to register at the XControl Facade '''before''' the event happens. | ||
* If Façade is not executing fast enough to keep up with data updates, it causes the updates to queue up. The updates will happen even after the VI stops running. To reduce data updates: | * If Façade is not executing fast enough to keep up with data updates, it causes the updates to queue up. The updates will happen even after the VI stops running. To reduce data updates: | ||
Thanks to Ram Kudukoli (of NI R&D) for sharing this with us at the recent CLA Summit: | Thanks to Ram Kudukoli (of NI R&D) for sharing this with us at the recent CLA Summit: | ||
| Line 35: | Line 30: | ||
== See also == | == See also == | ||
*[[QControl|QControls]] | *[[QControl|QControls]] | ||
[[Category:XControl]] | [[Category:XControl]] | ||
Revision as of 04:47, 1 December 2018
XControls were first introduced in LabVIEW 8 and enhance the power of front panel objects. An XControl is a front panel object with dedicated UI logic code linked and encapsulatedin the XControl in order to react to user events on the controls in contains. An XControl consists of several parts, managed in a .xctl file. The .xctl file is a XML-file like the project-file or Library files. Other parts of the XControl are called:
Limitations
An XControl functions like a subpanel in the hosting VI. Subpanels (and therefore XControls) can not be placed inside an array. Note that you can define your XControl data as an array of any LabVIEW data type, and you can use array controls in the facade vi.
Using LabVIEW native objects (.lvclass files) inside the state control of an XControl tends to crash LabVIEW for versions less than 8.5.1 when the XControl is used in a different application instance.
Also, XControls have limitations when running in VIs that are part of a Library (or Packed Project Library (PPL)), or a LabVIEW Class. This makes it difficult to use in a large application using Actor Framework or plugin architectures using PPLs. See more in the QControls article.
Tricks
- If you require a variable number of runtime instances of your XControl, Jarrod Slocum of National Instruments has created an example Linked Object List based on a Subpanel inside an XControl.
- If you want to react to dynamic events (or user events) you need them to register at the XControl Facade before the event happens.
- If Façade is not executing fast enough to keep up with data updates, it causes the updates to queue up. The updates will happen even after the VI stops running. To reduce data updates:
Thanks to Ram Kudukoli (of NI R&D) for sharing this with us at the recent CLA Summit:
- Open the Xcontrol .xctl file in a text editor like Notepad.
- Add the bolded line shown below:
<Property Name="NI.Lib.Version" Type="Str">1.0.0.0</Property> <Property Name="NI.XClass.Flags" Type="Int">0</Property> <Property Name="NI.XCtl.OptimizeDataUpdate" Type="Bool">true</Property> <Property Name="NI.XItem.DeclaredLeakProof" Type="Bool">false</Property>
- Save the .xctl file.