# Multi-Task Selection
Starting from version 3.2, the library provides the **multiselect** extension that allows you to select multiple tasks at once.
## Activating multi-task selection
To activate multi-task selection for tasks, enable it using the [gantt.plugins](api/method/plugins.md) method:
~~~js
gantt.plugins({ /*!*/
multiselect: true /*!*/
}); /*!*/
//your code will be here
~~~
[Multiselection and Indent/Outdent tasks](https://docs.dhtmlx.com/gantt/samples/02_extensions/09_multiselection.html)
Once the extension is activated, multi-task selection will be automatically enabled.
To disable extension, use the [multiselect](api/config/multiselect.md) option:
**Disabling multi-task selection**
~~~js
gantt.config.multiselect = false;
~~~
## One-time update for multiple tasks
To update multiple tasks/links at once, use the [batchUpdate](api/method/batchupdate.md) method:
~~~js
gantt.batchUpdate(function () {
var tasks = gantt.getTaskByTime();
for(var i = 0; i < tasks.length; i++){
var task = tasks[i];
task.start_date = gantt.date.add(task.start_date, 1, "day");
task.end_date = gantt.calculateEndDate(task.start_date, task.duration);
gantt.updateTask(task.id);
}
});
~~~
The method allows you to update multiple tasks/links at once with a single re-rendering instead of making multiple updates with multiple re-renderings.
[Multiselection and Indent/Outdent tasks](https://docs.dhtmlx.com/gantt/samples/02_extensions/09_multiselection.html)
## Iterator
To iterate over all selected tasks in the Gantt chart, use the [eachSelectedTask](api/method/eachselectedtask.md) method:
~~~js
gantt.batchUpdate(function () {
gantt.eachSelectedTask(function(task_id){
if(gantt.isTaskExists(task_id))
gantt.deleteTask(task_id);
});
});
~~~
[Multiselection and Indent/Outdent tasks](https://docs.dhtmlx.com/gantt/samples/02_extensions/09_multiselection.html)
## Simultaneous indentation/outdentation
Multi-task selection allows you to apply different operations to multiple tasks at once. For example, you can add an indentation/outdentation thereby transforming tasks to sub-tasks and vice versa.
[Multiselection and Indent/Outdent tasks](https://docs.dhtmlx.com/gantt/samples/02_extensions/09_multiselection.html)
## Checking if a task is selected
To check if a task is currenly selected, use the [isSelectedTask](api/method/isselectedtask.md) method:
~~~js
gantt.templates.task_class =
gantt.templates.grid_row_class =
gantt.templates.task_row_class = function (start, end, task) {
if (gantt.isSelectedTask(task.id))
return "gantt_selected";
};
~~~
[Multiselection and Indent/Outdent tasks](https://docs.dhtmlx.com/gantt/samples/02_extensions/09_multiselection.html)
To toggle between selected and unselected states, use the [toggleTaskSelection](api/method/toggletaskselection.md) method:
~~~js
gantt.toggleTaskSelection("t_1"); //"t_1" is the task's id
gantt.render();
~~~
## Getting all selected tasks
To get all tasks that are currently selected, use the [getSelectedTasks](api/method/getselectedtasks.md) method:
~~~js
gantt.getSelectedTasks();
~~~
To get the last selected task, use the [getLastSelectedTask](api/method/getlastselectedtask.md) method:
~~~js
gantt.getLastSelectedTask();
~~~
## Limiting multi-task selection within one level
To deny selecting tasks from different levels, use the [multiselect_one_level](api/config/multiselect_one_level.md) option:
~~~js
gantt.config.multiselect_one_level = true;
gantt.init('gantt_here');
~~~
## Multi-task selection and drag-n-drop {#multitaskselectionanddragndrop}
When the **multiselect.js** extension is activated, you can select several tasks by holding either the Ctrl or Shift key and drag the selected tasks horizontally at once.
To disable this functionality, set the [drag_multiple](api/config/drag_multiple.md) method to *false*:
~~~js
gantt.config.drag_multiple = true;
~~~
[Multiselection and Indent/Outdent tasks](https://docs.dhtmlx.com/gantt/samples/02_extensions/09_multiselection.html)
## Opening editor with one click
In the single selection mode, Gantt opens the inline editor after you click on a task.
In the **multi selection** mode, after you click on an unselected task, Gantt will select it, and will open the [inline editor](guides/inline-editing.md) only after the second click.
If you want Gantt to open the inline editor after the first click, enable the [inline_editors_multiselect_open](api/config/inline_editors_multiselect_open.md) config.
~~~js
gantt.plugins({
multiselect: true
});
...
gantt.config.inline_editors_multiselect_open = true;
~~~
## API events {#apievents}
When multi-task selection is enabled, selecting a task or a range of tasks will trigger both the general [onTaskSelected](api/event/ontaskselected.md) / [onTaskUnselected](api/event/ontaskunselected.md) events,
and events specific to the multiselect extension.
Multi-task selection has the following events flow:
- [onBeforeMultiSelect](api/event/onbeforemultiselect.md) - fires before selecting task or a range of tasks, blockable
- [onBeforeTaskMultiSelect](api/event/onbeforetaskmultiselect.md) - fires before task selection state is being changed (the task is being selected or unselected), blockable
- [onTaskMultiSelect](api/event/ontaskmultiselect.md) - fires after the task selection state has changed (the task has been selected/unselected)
- [onTaskUnselected](api/event/ontaskunselected.md) - is called for each task of the multiselection range
- [onTaskSelected](api/event/ontaskselected.md) - is called for each task of the multiselection range
- [onMultiSelect](api/event/onmultiselect.md) - fires after selection of a task or a range of tasks has been completed