CODEWITHSUNDEEP
c#.netlinq
erbeen
erbeen

Reputation: 77

Getting the largest value from an object in a list in another list [C#]

I have a big broblem.

I have a TaskGroup object. Each TaskGroup has: a 'Task' object and a List < TaskGroup > . (has a list of objects of itself in it). It is supposed to be a tree.

Having a 'TaskGroup' object that has 'List ' in it. I need to get the single largest Date value from the 'Task' object in each object in the 'TaskGroup' list.

public class TaskGroup
{
  public ProjectTask Task { get; set;}
  public List<TaskGroup> ChildTask { get; set; } = new List<TaskGroup>();
}
public class Task
{
  public int Id { get; set;}
  public DateTime Date { get; set; }
}

In the diagram - having "my object" I have to get the largest date marked in red.

enter image description here

Does anyone know how to do this? Thanks

Upvotes: 1

Views: 55

Answers (1)

Rufus L
Rufus L

Reputation: 37020

To get the largest date from the immediate children, you can just use a simple Linq statement:

var maxDate = taskGroup.ChildTask.Max(c => c.Task.Date);

To get the max date from all taskGroups under the main taskGroup, you can recursively check all the children for their max date:

static DateTime GetMaxDate(TaskGroup group)
{
    if (group == null) return DateTime.MinValue;

    var maxDate = group.Task?.Date ?? DateTime.MinValue;

    foreach (var child in group.ChildTask)
    {
        if (child.Task?.Date > maxDate) maxDate = child.Task.Date;

        foreach (var taskGroup in child.ChildTask)
        {
            var childMax = GetMaxDate(taskGroup);
            if (childMax > maxDate) maxDate = childMax.Date;
        }
    }

    return maxDate;
}

Upvotes: 2

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