LabVIEW
can you enable a scroll bar in a disabled control
I was playing around filtering all key own events on the string control. This prevents typing, but still allows scrolling because mouse-down is still allowed..
One interesting observation is that even if I filter out all key down events (event case: key down?, empty case, discard=true), I can still press ctrl+v and paste any amount of text into the text control. I guess copy/paste operation etc. are intercepted by the OS before the event structure can discard them. Strange....
@James.M wrote:
... unless altenbach's idea is implemented someday.
.CORRECT WOULD BE: .. unless the idea mentioned by altenbach is implemented someday....
(It is not my idea :D)
The more I think about it, the "disabled" property should have no effect on the scroll bar at all.
If the programmer does not want the control to be scrolled, he can hide the scrollbar.
Scrolling is not a data operation but a cosmetic UI feature.
Maybe only "dsiabled&Grayed" should disable the scrollbar?
@Hatef wrote:
what about my method that I send it in my last post ?!
There are plenty of solutions presented here. Are you expecting a detailed discussion of your VI? Nobody else does. 😄
OK, here are some comments to your last attachment:
- First of all, the stop terminal is still outside the stop event. Why not eliminate the true diagram constant and place the terminal in its place?
- The "solution" is still cluttered with irrelevant code that has nothing to do with the question, such as updating the scroll position in a second indicator. Nobody asked for that.
- A "select" function would be cleaner than the inner case structure, because it shows all code at once.
- It would be simpler to define a value change event on the entire cluster, no need to exclude the string and separately list all other controls in the cluster. A string value change cannot occur because the control is disabled. Now you only have two instead of four event conditions, making the code more readable.
- If the user toggles the "string control mode" during editing, the control states are initially inconsistent. You need initialization code.
- Why are your terminal labels so gigantic?
- Instead of a classic vertical slide, you should use a modern vertical scroll bar control. Nobody expects a slide to act as a scrollbar. The UI needs to be intuitive!
- The slide range does not adapt to the text lenght. For example if we add a few more paragraphs to the string, we no longer can scroll to the bottom
- ...
Hatef wrote:first why should i do that or even do not do that it is just to make event and there no important where there is ! is it?
I assume you are talking about the comment about the stop terminal placement.
The stop button is latch action, meaning it gets reset to false once it is in the non-default state and read by the code. If it is outside the event structure, it gets read by the code before the event occurs and, after the stop event occurs, the VI stops without reading the terminal once more. Newer versions of LabVIEW also seem to reset once the VI stops, but it is a general rule that latch action booleans should be in their respective event cases or there needs to be code in place that force a new read after certain other things have occurred, for example.
Placing latch action terminals inside their respective event case is an excellent habit and exceptions should be rare and well researched. It is also a good debugging tool, because if the button does not reset during run, it means that the event did not fire, probably because of faulty code.
