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Inspired by a project posted here, I wanted a way to have a devloper make a UI that has selection of items, using checkboxes. This is a common control a user may see during development, but in LabVIEW it is a more difficult thing to implement with symbols on controls. So attached is some demo code which expands on that document.
This demo supports right click for select all, select none, and invert selection. It also supports using the shift key to select and deselect multiple items. The tree control also supports selecting and deselecting a parent, which propagates to all the children.
Source is saved in 2011 and require the OpenG array package.
Version 5 - Bug fixes to the tree selection preventing you from modifying a disabled item by editing a parent, and fixed a bug where a parent might appear mixed in large nested trees.
http://sine.ni.com/nips/cds/view/p/lang/en/nid/209027
Basically install VI Package Manager, and install the OpenG Array package, and its dependencies.
Okay this is possible but might be a pain. Perform a Key Down? event on the Tree control, then in the event look to see if the spacebar was pressed (ScanCode == 57). If so then get the Active Cell >> Position using a property node. Then use the Well you could capture a key down? filter event on the tree control, and then perform the Selection Handle Mouse Down and pass in the cell position. This won't work but will be close. If you look at the X and Y returned by Cell Position it will be a little off. This is because this is the coordinates of the top left of the cell which, next we'd need to take into account the intent level.
Or you can go the Force Selection route. This seems to work well for children, but a parent selection change isn't working, you'd need to figure out how to handle that.
QControls are starting to gain popularity and as a result I turned this into one, well three actually but from the palette you wouldn't know that because there is a polymorphic VI that selects the appropriate QControl based on the reference wired. The core of the code is the same as what was posted here but now the code can be put into the a class instead of having extra code be handled in the main application. Also it is distributed as a package with a palette.
Very neat. Yes I see where there could be a large performance issue with the multiple nested loops getting various tag information. When developing this I primarily was thinking of a set of test selections that are populate at runtime. I think I had a folder of VIs that were dynamically loaded and ran. So to add a new test you just put a VI in a folder, and now the user can select that test to run. This meant I only ever saw a couple dozen tags at once. Caching the data at the start is a much better technique, assuming you don't update the tags after the initial display. And in a UX like this I think is a pretty normal expectation. There might be a performance gain if you use the native Map functions, but what you have now is probably good enough.
Programmatically changing a tree at runtime is a thing LabVIEW can do. It isn't very straight forward to new users and it I'm unsure of what examples you'll find online. This uses the Property and Invoke nodes using the reference of a tree control. Drop down a tree control then right click it and go to Create >> Invoke Node >> Edit Tree Items >> Delete Item. Drop this invoke node on the block diagram. There are other nodes like Add Item and Move Item. Open the context help with CTRL+H and then when you hover over an item it will give you instructions on how to use it. Using these functions you can edit the tree items. It takes a lot of experimentation and experience to get good at these functions and new developers are going to struggle.
