DHTMLX Planning Engine Documentation

AssignmentUpdate#

An edit to one existing assignment of a live project. It goes in the Update list of SchedulingChanges.Assignments, which Project.Apply and Project.Preview take. Create it with new AssignmentUpdate(id) and set the fields to change in an object initializer.

Declaration#

namespace Plen;

public sealed class AssignmentUpdate : IDeepCloneable<AssignmentUpdate>

Constructors#

AssignmentUpdate(Id)#

public AssignmentUpdate(Id id)

Creates an update for the assignment with the given id. Every other property is Patch<T>.Missing, so the update changes nothing until a property is set.

Name Type Description
id Id Id of the assignment to edit. A string, int or double converts implicitly.

Properties#

Every property except Id is a Patch<T>. Missing (the default) keeps the stored value, a value sets it, and Null clears it. The On Null column shows what Null does. For the meaning of each value, see the property of the same name on AssignmentData.

A plain value converts implicitly to a Patch<T>, so Value = 0.5 works. An Id property needs Patch<Id>.Of(...) when the value is a string or a number, because C# doesn't chain the two implicit conversions.

Property Type On Null Description
Id Id required Id of the assignment to edit.
Task Patch<Id> rejected Moves the assignment to another task.
Resource Patch<Id> rejected Gives the assignment to another resource.
Value Patch<double> rejected New units booked.
Offset Patch<double> null New start of the slice. null books from the task start.
Duration Patch<double> null New length of the slice. null books up to the task end.

The edited assignment must still meet the AssignmentData rules: Value and Duration greater than 0, Offset 0 or greater, and Task and Resource naming existing records.

Effect on dates#

  • Offset, Duration and Value change resource load only. They never move a task.
  • Task and Resource move dates only when the task then works on a different set of calendars, for example when the new resource has its own calendar in CalendarMode.Resource.
  • Moving an assignment to an unscheduled task keeps it in the project without booking load. Its id is listed in ChangeEffects.DroppedAssignments.

Methods#

DeepClone#

public AssignmentUpdate DeepClone()

Returns a copy with the same property values.

Returns: a new AssignmentUpdate.

ToString#

public override string ToString()

Returns a debug dump of the fields, e.g. AssignmentUpdate { Id: a1, Task: Missing, Resource: Missing, … }.

Errors#

An update is rejected as a single operation, at path assignments.update[i]. Project.Apply and Project.Preview describe how a rejection is reported.

Message When it occurs
unknown assignment id No assignment has Id.
required field cannot be null Task, Resource or Value is Null.
a validation message The edited assignment breaks an AssignmentData rule, for example an unknown Resource or a Value of 0.

Example#

Hand Ben's review to Cara and narrow it to the last day of the task:

using Plen;

var start = Moment.FromYmdHm(2026, 4, 6, 8, 0)
    ?? throw new InvalidOperationException("invalid date");

var data = new ProjectData
{
    Tasks = [new TaskData(1) { StartDate = start, Duration = 5.0 }],
    Resources =
    [
        new ResourceData { Id = "ben" },
        new ResourceData { Id = "cara" },
    ],
    Assignments =
    [
        new AssignmentData { Id = "review", Task = 1, Resource = "ben", Value = 0.5 },
    ],
};

var project = new Project();
project.Solve(data, new SolveOptions());

var changes = new SchedulingChanges();
changes.Assignments.Update.Add(new AssignmentUpdate("review")
{
    Resource = Patch<Id>.Of("cara"),
    Offset = 4.0,
    Duration = 1.0,
});

var report = project.Apply(changes);
foreach (var rejected in report.Rejected)
{
    Console.WriteLine($"{rejected.Path}: {rejected.Message}");
}