Way to find previous element within a panel

GoJS
1

Hi,

Is there any way in element property binding function to get the previous element related to itself within a same panel?

sample code:

$(go.Panel, 'Horizontal', {},
    $(go.TextBlock, 'First Label'),
    $(go.TextBlock, 'Second Label',
         new go.Binding('stroke', '', function(data, target){
                
             //Any APIs to get first textblock ( something like target.getPrevElement()) ?

         }))
)
2

There isn’t anything exactly like .nextSibling or .previousSibling.

But you could do something like:

  $(go.Node, ...,
    $(go.TextBlock, "First Label", { name: "FIRST" }, ...),
    $(go.TextBlock, "Second Label", ...,
       new go.Binding("stroke", "", function(tb) { ... }).ofObject("FIRST")
    )
  )

In fact, if you are just going to use some settable property of the “FIRST” TextBlock as the value of the second TextBlock.stroke, you don’t even need a converter function:

  $(go.Node, ...,
    $(go.TextBlock, "First Label", { name: "FIRST" }, ...,
       new go.Binding("stroke", "color")),  // based on data.color
    $(go.TextBlock, "Second Label", ...,
       new go.Binding("stroke", "stroke").ofObject("FIRST")  // on 1st TextBlock.stroke
    )
  )

Note that element names (i.e. GraphObject.name), allowing one to call Panel.findObject, are scoped at each Part or each item Panel.

3

Hi Walter:

Thanks for the quick response.

I was try to avoid set name property since there are many textblocks in a panel, and each textblock’s stroke is exactly related on its previous textblock, I was thought using findObject may cause some performance issue as the textblock list growth.

4

No, sorry, there aren’t any such “relative source” bindings at this time. It’s been on the list of maybe-someday features since v0.0, though.