Project Management

What it is for

Use it wherever people plan work against dates: a project plan, a release schedule, a production run, a fit-out programme. The task list on the left is a tree grid – outline number, name, dates, length, progress, assignee and predecessors – and the timeline on the right shows each task as a bar on the calendar, with weekends and holidays shaded, a line at today and the critical path picked out in its own colour. A splitter between the two moves the boundary.

The plan

Give the chart a list of ProjectTask objects in Tasks and the dependencies between them as TaskLink objects in Links. A task becomes a summary when other tasks name it as their ProjectTask.ParentId, and a milestone when its duration is zero. The chart never keeps dates of its own: it schedules the plan on the working calendar of ProjectStart, WorkingWeek and Holidays (see ProjectScheduler) and draws the result, which Schedule returns. Data that cannot be used – a duplicate id, a link to a missing task, a loop – is reported in ProjectSchedule.Problems, and everything else is still drawn.

Use an ObservableCollection or a BindingList for the two lists and the chart watches them and every object in them: add a task, change a duration, and the chart schedules again and redraws. Give the same two collections to a PertChart and a TaskBoard and all three show one plan; an edit made in any of them is seen by the others at once.

Editing

A reader can drag a bar to move it, drag its end to change its length, drag the small triangle under it to record progress, and drag from the dot at its end to another bar to link the two. A slow second click on a cell, or F2, edits it: the name, the start, the length, the progress, or the predecessors, typed as a planner writes them (2, 3SS+1). Every edit is offered first through the cancelable TaskChanging or LinksChanging event, then written to the task or link objects themselves, then announced by TaskChanged or LinksChanged – so an application enforces its own rules in one handler, whichever way the edit was made. ReadOnly turns editing off.

Keyboard

The wheel scrolls the rows, with Shift scrolls sideways, and with Ctrl zooms about the date under the pointer. Each row is exposed to screen readers as an outline item that says the task's dates, length, progress and whether it is critical.

Appearance

The bars, the critical path, summaries, baselines and the today line each have a colour of their own (BarColor, CriticalBarColor and so on). The grid lines, weekend shading, links and headers default to shades worked out from Control.ForeColor and BackColor, so setting those two for a dark theme gives a dark chart. In Windows high-contrast mode the system colours are used instead. The timeline's scale is Zoom; every size is in logical pixels (1/96 inch) and scales with the display. ExportImage and CreatePrintDocument draw the whole plan as an image or across printed pages.

A form showing an eight-task website plan, with the assignee and progress columns added, a rule that finished work cannot be moved, and the finish date in the title bar. On a Monday-to-Friday week from 2 November 2026 the plan finishes on 1 December 2026, and the critical path runs through the brief, the wireframes, the front end, testing and go-live.

using System;
using System.Collections.ObjectModel;
using System.Drawing;
using System.Windows.Forms;
using Binarymission.WinForms.Controls.ProjectManagement;

public sealed class PlanForm : Form
{
    private readonly GanttChart _gantt = new GanttChart();
    private readonly ObservableCollection<ProjectTask> _tasks = new ObservableCollection<ProjectTask>();
    private readonly ObservableCollection<TaskLink> _links = new ObservableCollection<TaskLink>();

    public PlanForm()
    {
        Text = "Website relaunch";
        Size = new Size(1100, 520);

        _tasks.Add(new ProjectTask("design", "Design"));
        _tasks.Add(new ProjectTask("brief", "Agree the brief", 3) { ParentId = "design", Assignee = "Priya", Progress = 100 });
        _tasks.Add(new ProjectTask("wire", "Wireframes", 5) { ParentId = "design", Assignee = "Priya", Progress = 40 });
        _tasks.Add(new ProjectTask("build", "Build"));
        _tasks.Add(new ProjectTask("front", "Front end", 10) { ParentId = "build", Assignee = "Tom" });
        _tasks.Add(new ProjectTask("api", "Order API", 8) { ParentId = "build", Assignee = "Aisha" });
        _tasks.Add(new ProjectTask("test", "User testing", 4) { Assignee = "Priya" });
        _tasks.Add(new ProjectTask("live", "Go live", 0));

        _links.Add(new TaskLink("brief", "wire"));
        _links.Add(new TaskLink("wire", "front"));
        _links.Add(new TaskLink("wire", "api", TaskLinkType.StartToStart, 2));
        _links.Add(new TaskLink("build", "test"));
        _links.Add(new TaskLink("test", "live"));

        _gantt.Dock = DockStyle.Fill;
        _gantt.Tasks = _tasks;
        _gantt.Links = _links;
        _gantt.ProjectStart = new DateTime(2026, 11, 2);
        _gantt.Holidays.Add(new DateTime(2026, 12, 25));
        _gantt.Columns = GanttColumns.Default | GanttColumns.Assignee | GanttColumns.Progress;
        _gantt.TaskChanging += OnTaskChanging;
        _gantt.ScheduleChanged += (sender, e) => ShowFinish();
        Controls.Add(_gantt);

        Load += (sender, e) =>
        {
            ShowFinish();
            _gantt.ZoomToFit();
        };
    }

    private void OnTaskChanging(object sender, TaskChangingEventArgs e)
    {
        // Finished work stays where it is; its name can still be corrected.
        if (e.Task.Progress >= 100 && (e.NewStart.HasValue || e.NewDuration.HasValue))
            e.Cancel = true;
    }

    private void ShowFinish()
    {
        Text = "Website relaunch - finishes " + _gantt.Schedule.ProjectFinish.ToString("d MMM yyyy");
    }
}