Tasks and Calendars

In Microsoft Project, it is possible to associate specific calendars with individual tasks. Aspose.Tasks for .NET provides the same capability through the Tsk.Calendar property, which links a task to a particular calendar.

Tasks with Calendars

The Tsk class exposes the Calendar field used to set or get the calendar associated with a task. This property accepts or returns an Aspose.Tasks.Calendar object.

To create a calendar for a task in Microsoft Project:

1. Open the project file.
2. On the Project menu, select Change Working Times → Create New Calendar.
3. To assign the calendar, double-click a task in the Task Entry form and select the calendar in the task properties.

Example: Setting a Task Calendar

The following code shows how to create a calendar, add a task, and assign the calendar to it:

Project project = new Project();

// Add task
Task task = project.RootTask.Children.Add("Task1");

// Create calendar and assign to task
Calendar cal = project.Calendars.Add("TaskCal1");
task.Set(Tsk.Calendar, cal);

Example: Reading a Task Calendar

You can also traverse tasks in a project and read their associated calendars:

Project project = new Project("New Project.mpp");

// Declare ChildTasksCollector class object
ChildTasksCollector collector = new ChildTasksCollector();

// Use TaskUtils to get all children tasks in RootTask
TaskUtils.Apply(project.RootTask, collector, 0);

// Parse all the recursive children
foreach (Task task in collector.Tasks)
{
    Calendar cal = task.Get(Tsk.Calendar);
    Console.WriteLine("Task calendar name: {0}", cal == null ? "None" : cal.Name);
}

Key Notes

• Task calendars override the project calendar for scheduling that specific task.
• If a task does not have its own calendar, it inherits the default project calendar.
• Calendars can include working times, exceptions, and holidays, providing fine-grained control over task scheduling.
• Works consistently across both MPP and XML formats.

FAQ

Q: Can a task have more than one calendar?

• No. Each task can only be assigned a single calendar.

Q: What happens if a task calendar conflicts with the project calendar?

• The task calendar takes precedence for that task.

Q: How can I remove a calendar from a task?

• Set the task’s Calendar property to null to make it use the project calendar again.

Q: Are resource calendars considered when assigning task calendars?

• Yes. The final schedule is calculated by combining task calendars, resource calendars, and the project calendar.