It is quite common to want to use a cell that acts on an entire
row. You may want to pop up a modal, delete the row, or toggle
editibility for all the columns. The possibilities are endless. For
those cases, you can write a custom
ActionCell, and then
pass it to the column definition.
The easiest way to do it is to extend your models from a
Backbone.Model subclass that supports computed
properties and accessing them via the same get/set
interface. There are a number of Backbone plugins readily available for
this. Should all else failed, you can roll your own fairly
See the sorting programmatically section.
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Some data grid widgets out there support a technique called adaptive scrolling, meaning the DOM elements will be swapped out of a viewport and new ones appended as the models are loaded from the server, thus keeping the memory more or less constant while providing an illusion to end-users that there's no limit to the number of rows the data grid can handle.
Backgrid.js has something better and achieves the same effect with much cleaner code - paginator extension, which uses backbone.paginator. The paginator supports both paging on the server-side, or preloading all the models and paging purely through the browser. Paginated Backgrid.Grid instances only render one page of DOM nodes at a time to save memory and keep your web page responsive.
No, because it is not the goal of this project to produce a full-fledged web-based spreadsheet. However, doing aggregation is trivial using Underscore.js methods.
If you use a Backbone plugin that supports computed values, you may also treat the computed values as a column as well.
Inside a Backgrid grid, every cell listens to the change event for its model value. The cells will rerender themselves during display mode upon changes in the model values. However, this functionality is only meant for synchronizing data automatically across multiple grids on the same page. If you are attempting to synchronize data changes across multiple processes, you will need some kind of a locking mechanism for the individual cells, Backgrid.js provides no help for that and you have to do this yourself. Implementing such web-based spreadsheet-like broker system is outside of the scope of this project, pull requests are welcome however.
If the feature you have in mind isn't found here in this Backgrid.js version, it could either be in the works or under consideration.
See the list of tasks and enhancements.