Task definition in Gantt Chart Library and Project Management Library for WPF

The tasks within Gantt Chart Library for WPF or Project Management Library for WPF are defined using these main timing related properties:

Schedule: defines working and nonworking time for the task on the timeline (for example, Monday-Friday 8 AM - 4 PM is working time, each week, no holidays); if schedule is null for a specific task (default situation), the main TaskManager (or control) level schedule definition is used;
Start: date and time value (such as Jan. 3, 2011, 8 AM);
Effort: actual required work time span, considered when a single resource would be fully assigned to perform it (such as 1 day and 4 hours, i.e. 30 work hours);
Assignments: defines resources assigned to the task, and their allocation units (for example, both John and Mary may be assigned to the same task, but Mary may use only 50% of its availability for this specific work item, i.e. 0.5 allocation units); by default, if no assignments are specified, allocation units total is considered to be 100% (1);
Duration: defines the value of the effort divided to the sum of assignment allocation units (for the previous example: Duration = 30 hours / (1 + 0.5) = 30 / 1.5 = 20 hours, i.e. the 30 hours effort can be performed in a time span of only 20 hours, by fully allocated John together with half allocated Mary);
Finish: date and time value computed by adding the duration time span (applied to the specified task schedule) to the start date and time (for the previous example, the finish date and time would be Jan. 5, 2011, 12 PM; because the task has a duration of 20h, and schedule is set to 8h/day from Monday to Friday, so the task would end on Wednesday at noon, as it starts on Monday at 8 AM). Note that when DurationMemberPath and EffortMemberPath are set to null at TaskManager (or control) level, the finish value of the task is not automatically computed, but instead its duration and effort are automatically computed based on the provided finish date and time.