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Diffstat (limited to 'documentation/components')
| -rw-r--r-- | documentation/components/components-treegrid.asciidoc | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/documentation/components/components-treegrid.asciidoc b/documentation/components/components-treegrid.asciidoc index d3a431c3e9..f3c2058f03 100644 --- a/documentation/components/components-treegrid.asciidoc +++ b/documentation/components/components-treegrid.asciidoc @@ -93,6 +93,22 @@ treeGrid.addColumn(Project::getHoursDone).setCaption("Hours Done"); treeGrid.setHierarchyColumn("name"); ---- +== Prevent Node Collapsing + +[classname]#TreeGrid# supports setting a callback method that can allow or prevent the user from collapsing an expanded node. +It can be set with [methodname]#setItemCollapseAllowedProvider# method, that takes a [interfacename]#SerializablePredicate#. +For nodes that cannot be collapsed, the [literal]#++collapse-disabled++# class name is applied to the expansion element + +Avoid doing any heavy operations in the method, since it is called for each item when it is being sent to the client. + +Example using a predefined set of persons that can not be collapsed: +[source, java] +---- +Set<Person> alwaysExpanded; +personTreeGrid.setItemCollapseAllowedProvider(person -> + !alwaysExpanded.contains(person)); +---- + == Listening to Events In addition to supporting all the listeners of the standard [classname]#Grid#, [classname]#TreeGrid# supports listening to the expansion and collapsing of items in its hierarchy. |