Blazorise Gantt component

@code {
    private DateOnly selectedDate = DateOnly.FromDateTime( DateTime.Today );

    private List<TaskItem> tasks = CreateTasks();

    private static List<TaskItem> CreateTasks()
    {
        var baseDate = DateTime.Today.AddDays( -2 );

        var result = new List<TaskItem>
        {
            new() { Id = "1", Title = "Website redesign", Start = baseDate, End = baseDate.AddDays( 16 ) },
            new() { Id = "2", ParentId = "1", Title = "Discovery", Start = baseDate, End = baseDate.AddDays( 4 ) },
            new() { Id = "3", ParentId = "1", Title = "Implementation", Start = baseDate.AddDays( 4 ), End = baseDate.AddDays( 14 ) },
            new() { Id = "4", ParentId = "3", Title = "Components", Start = baseDate.AddDays( 5 ), End = baseDate.AddDays( 10 ) },
            new() { Id = "5", ParentId = "3", Title = "Accessibility pass", Start = baseDate.AddDays( 10 ), End = baseDate.AddDays( 13 ) },
            new() { Id = "6", ParentId = "1", Title = "Launch", Start = baseDate.AddDays( 14 ), End = baseDate.AddDays( 16 ) },
        };

        foreach ( var item in result )
        {
            item.Duration = Math.Max( 1, (int)Math.Ceiling( ( item.End - item.Start ).TotalDays ) );
        }

        return result;
    }

    public class TaskItem
    {
        public string Id { get; set; }

        public string ParentId { get; set; }

        public string Title { get; set; }

        public DateTime Start { get; set; }

        public DateTime End { get; set; }

        public int Duration { get; set; }
    }
}

@code {
    private DateOnly selectedDate = DateOnly.FromDateTime( DateTime.Today );

    private List<TaskItem> tasks = CreateTasks();

    private static List<TaskItem> CreateTasks()
    {
        var baseDate = DateTime.Today.AddDays( -2 );

        var result = new List<TaskItem>
        {
            new()
            {
                Id = "1",
                Title = "Mobile app release",
                Start = baseDate,
                End = baseDate.AddDays( 18 ),
                Children = new()
                {
                    new()
                    {
                        Id = "2",
                        Title = "Planning",
                        Start = baseDate,
                        End = baseDate.AddDays( 4 ),
                    },
                    new()
                    {
                        Id = "3",
                        Title = "Execution",
                        Start = baseDate.AddDays( 4 ),
                        End = baseDate.AddDays( 16 ),
                        Children = new()
                        {
                            new()
                            {
                                Id = "4",
                                Title = "API integration",
                                Start = baseDate.AddDays( 5 ),
                                End = baseDate.AddDays( 11 ),
                            },
                            new()
                            {
                                Id = "5",
                                Title = "QA",
                                Start = baseDate.AddDays( 11 ),
                                End = baseDate.AddDays( 16 ),
                            },
                        },
                    },
                    new()
                    {
                        Id = "6",
                        Title = "Go-live",
                        Start = baseDate.AddDays( 16 ),
                        End = baseDate.AddDays( 18 ),
                    },
                },
            },
        };

        UpdateDuration( result );

        return result;
    }

    private static void UpdateDuration( IEnumerable<TaskItem> items )
    {
        foreach ( var item in items )
        {
            item.Duration = Math.Max( 1, (int)Math.Ceiling( ( item.End - item.Start ).TotalDays ) );
            UpdateDuration( item.Children );
        }
    }

    public class TaskItem
    {
        public string Id { get; set; }

        public string Title { get; set; }

        public DateTime Start { get; set; }

        public DateTime End { get; set; }

        public int Duration { get; set; }

        public List<TaskItem> Children { get; set; } = new();
    }
}

@code {
    private DateOnly selectedDate = DateOnly.FromDateTime( DateTime.Today );

    private List<TaskItem> tasks = CreateTasks();

    private static List<TaskItem> CreateTasks()
    {
        var baseDate = DateTime.Today.AddDays( -2 );

        var result = new List<TaskItem>
        {
            new() { Id = "1", Title = "Marketing campaign", Start = baseDate, End = baseDate.AddDays( 15 ), Progress = 45d },
            new() { Id = "2", ParentId = "1", Title = "Research", Start = baseDate, End = baseDate.AddDays( 4 ), Progress = 100d },
            new() { Id = "3", ParentId = "1", Title = "Creative", Start = baseDate.AddDays( 4 ), End = baseDate.AddDays( 9 ), Progress = 70d },
            new() { Id = "4", ParentId = "1", Title = "Distribution", Start = baseDate.AddDays( 9 ), End = baseDate.AddDays( 15 ), Progress = 20d },
        };

        foreach ( var item in result )
        {
            item.Duration = Math.Max( 1, (int)Math.Ceiling( ( item.End - item.Start ).TotalDays ) );
        }

        return result;
    }

    private bool AllowCommand( GanttCommandContext<TaskItem> context )
    {
        if ( context.CommandType == GanttCommandType.Delete && context.Item?.ParentId is null )
            return false;

        return true;
    }

    public class TaskItem
    {
        public string Id { get; set; }

        public string ParentId { get; set; }

        public string Title { get; set; }

        public DateTime Start { get; set; }

        public DateTime End { get; set; }

        public int Duration { get; set; }

        public double Progress { get; set; }
    }
}

@code {
    private DateOnly selectedDate = DateOnly.FromDateTime( DateTime.Today );
    private List<TaskItem> tasks = CreateTasks();
    private bool editorVisible;
    private string editorModeTitle = "Edit task";
    private string editorTitle;
    private string editorParentId;
    private string editorTargetId;
    private TaskItem editorDraft;
    private string lastAction = "None";
    private int nextId = 100;

    private Task OnNewItemClicked( GanttCommandContext<TaskItem> context )
        => OpenEditor( context.Item, null, null, "Create task" );

    private Task OnAddChildItemClicked( GanttCommandContext<TaskItem> context )
        => OpenEditor( context.Item, context.ParentItem, null, $"Create child for {context.ParentItem?.Title}" );

    private Task OnEditItemClicked( GanttItemClickedEventArgs<TaskItem> context )
        => OpenEditor( context.Item, null, context.Item?.Id, $"Edit {context.Item?.Title}" );

    private Task OnDeleteItemClicked( GanttItemClickedEventArgs<TaskItem> context )
    {
        if ( context?.Item?.Id is null )
            return Task.CompletedTask;

        RemoveTaskWithChildren( tasks, context.Item.Id );
        lastAction = $"Deleted {context.Item.Title}";

        return Task.CompletedTask;
    }

    private Task OpenEditor( TaskItem item, TaskItem parentItem, string targetId, string modeTitle )
    {
        editorDraft = item?.Clone() ?? new TaskItem();
        editorParentId = parentItem?.Id;
        editorTargetId = targetId;
        editorTitle = editorDraft.Title ?? string.Empty;
        editorModeTitle = modeTitle;
        editorVisible = true;

        return Task.CompletedTask;
    }

    private Task CloseEditor()
    {
        editorVisible = false;
        editorDraft = null;
        editorParentId = null;
        editorTargetId = null;
        editorTitle = string.Empty;

        return Task.CompletedTask;
    }

    private Task SaveEditor()
    {
        if ( editorDraft is null )
            return Task.CompletedTask;

        editorDraft.Title = string.IsNullOrWhiteSpace( editorTitle )
            ? "Untitled task"
            : editorTitle.Trim();

        if ( string.IsNullOrEmpty( editorTargetId ) )
        {
            editorDraft.Id ??= $"task-{nextId++}";
            editorDraft.ParentId = editorParentId;
            tasks.Add( editorDraft.Clone() );
            lastAction = editorParentId is null
                ? $"Created {editorDraft.Title}"
                : $"Created child {editorDraft.Title}";
        }
        else
        {
            var existingTask = tasks.FirstOrDefault( x => x.Id == editorTargetId );

            if ( existingTask is not null )
            {
                existingTask.Title = editorDraft.Title;
                lastAction = $"Updated {existingTask.Title}";
            }
        }

        return CloseEditor();
    }

    private static void RemoveTaskWithChildren( List<TaskItem> list, string itemId )
    {
        var idsToDelete = new HashSet<string>( StringComparer.Ordinal ) { itemId };
        var changed = true;

        while ( changed )
        {
            changed = false;

            foreach ( var task in list )
            {
                if ( task.ParentId is not null && idsToDelete.Contains( task.ParentId ) && idsToDelete.Add( task.Id ) )
                    changed = true;
            }
        }

        list.RemoveAll( x => idsToDelete.Contains( x.Id ) );
    }

    private static List<TaskItem> CreateTasks()
    {
        var baseDate = DateTime.Today.AddDays( -2 );

        return new List<TaskItem>
        {
            new() { Id = "1", Title = "Website redesign", Start = baseDate, End = baseDate.AddDays( 14 ), Duration = 14 },
            new() { Id = "2", ParentId = "1", Title = "Discovery", Start = baseDate, End = baseDate.AddDays( 4 ), Duration = 4 },
            new() { Id = "3", ParentId = "1", Title = "Implementation", Start = baseDate.AddDays( 4 ), End = baseDate.AddDays( 12 ), Duration = 8 },
            new() { Id = "4", ParentId = "1", Title = "Launch", Start = baseDate.AddDays( 12 ), End = baseDate.AddDays( 14 ), Duration = 2 },
        };
    }

    public class TaskItem
    {
        public string Id { get; set; }

        public string ParentId { get; set; }

        public string Title { get; set; }

        public DateTime Start { get; set; }

        public DateTime End { get; set; }

        public int Duration { get; set; }

        public TaskItem Clone()
        {
            return new TaskItem
            {
                Id = Id,
                ParentId = ParentId,
                Title = Title,
                Start = Start,
                End = End,
                Duration = Duration,
            };
        }
    }
}

@code {
    private DateOnly selectedDate = DateOnly.FromDateTime( DateTime.Today );

    private GanttView selectedView = GanttView.Week;

    private List<TaskItem> tasks = CreateTasks();

    private static List<TaskItem> CreateTasks()
    {
        var baseDate = DateTime.Today.AddDays( -2 );

        var result = new List<TaskItem>
        {
            new() { Id = "1", Title = "Project launch", Start = baseDate, End = baseDate.AddDays( 18 ) },
            new() { Id = "2", ParentId = "1", Title = "Planning", Start = baseDate, End = baseDate.AddDays( 4 ) },
            new() { Id = "3", ParentId = "1", Title = "Execution", Start = baseDate.AddDays( 4 ), End = baseDate.AddDays( 16 ) },
            new() { Id = "4", ParentId = "3", Title = "Backend", Start = baseDate.AddDays( 5 ), End = baseDate.AddDays( 11 ) },
            new() { Id = "5", ParentId = "3", Title = "Frontend", Start = baseDate.AddDays( 8 ), End = baseDate.AddDays( 15 ) },
            new() { Id = "6", ParentId = "1", Title = "Go-live", Start = baseDate.AddDays( 16 ), End = baseDate.AddDays( 18 ) },
        };

        foreach ( var item in result )
        {
            item.Duration = Math.Max( 1, (int)Math.Ceiling( ( item.End - item.Start ).TotalDays ) );
        }

        return result;
    }

    public class TaskItem
    {
        public string Id { get; set; }

        public string ParentId { get; set; }

        public string Title { get; set; }

        public DateTime Start { get; set; }

        public DateTime End { get; set; }

        public int Duration { get; set; }
    }
}

@code {
    private bool autoExpandView = true;

    private DateOnly selectedDate = DateOnly.FromDateTime( DateTime.Today.AddMonths( -3 ) );

    private GanttView selectedView = GanttView.Week;

    private List<TaskItem> tasks = CreateTasks();

    private static List<TaskItem> CreateTasks()
    {
        DateTime rangeStart = new DateTime( DateTime.Today.Year, DateTime.Today.Month, 1 ).AddDays( -4 );

        List<TaskItem> result = new()
        {
            new() { Id = "1", Title = "Auto-expand release", Start = rangeStart, End = rangeStart.AddDays( 41 ) },
            new() { Id = "2", ParentId = "1", Title = "Design phase", Start = rangeStart, End = rangeStart.AddDays( 8 ) },
            new() { Id = "3", ParentId = "1", Title = "Implementation", Start = rangeStart.AddDays( 7 ), End = rangeStart.AddDays( 28 ) },
            new() { Id = "4", ParentId = "3", Title = "Backend services", Start = rangeStart.AddDays( 9 ), End = rangeStart.AddDays( 18 ) },
            new() { Id = "5", ParentId = "3", Title = "Frontend polish", Start = rangeStart.AddDays( 16 ), End = rangeStart.AddDays( 31 ) },
            new() { Id = "6", ParentId = "1", Title = "Validation and rollout", Start = rangeStart.AddDays( 30 ), End = rangeStart.AddDays( 41 ) },
        };

        foreach ( TaskItem item in result )
        {
            item.Duration = Math.Max( 1, (int)Math.Ceiling( ( item.End - item.Start ).TotalDays ) );
        }

        return result;
    }

    public class TaskItem
    {
        public string Id { get; set; }

        public string ParentId { get; set; }

        public string Title { get; set; }

        public DateTime Start { get; set; }

        public DateTime End { get; set; }

        public int Duration { get; set; }
    }
}

@code {
    private DateOnly selectedDate = DateOnly.FromDateTime( DateTime.Today );

    private List<TaskItem> tasks = CreateTasks();

    private static List<TaskItem> CreateTasks()
    {
        var baseDate = DateTime.Today.AddDays( -2 );

        var result = new List<TaskItem>
        {
            new() { Id = "1", Title = "Platform update", Start = baseDate, End = baseDate.AddDays( 13 ) },
            new() { Id = "2", ParentId = "1", Title = "Core services", Start = baseDate, End = baseDate.AddDays( 7 ) },
            new() { Id = "3", ParentId = "1", Title = "Web client", Start = baseDate.AddDays( 4 ), End = baseDate.AddDays( 11 ) },
            new() { Id = "4", ParentId = "1", Title = "Release prep", Start = baseDate.AddDays( 11 ), End = baseDate.AddDays( 13 ) },
        };

        foreach ( var item in result )
        {
            item.Duration = Math.Max( 1, (int)Math.Ceiling( ( item.End - item.Start ).TotalDays ) );
        }

        return result;
    }

    public class TaskItem
    {
        public string Id { get; set; }

        public string ParentId { get; set; }

        public string Title { get; set; }

        public DateTime Start { get; set; }

        public DateTime End { get; set; }

        public int Duration { get; set; }
    }
}