Question

I am trying to populate a tree view based on a list of staff from various deparments (lstStaff).

public class Staff
{
    public int StaffID { get; set; }
    public string StaffName { get; set; }
    public int DeptID { get; set; }
    public string DepartmentName { get; set; }
}

The result should be like this:

Department A

• John
• Dave

Department B

• Andy
• Leon

I have written the following code. However, I think the code should be refactored further.

RadTreeNode deptNode;
RadTreeNode staffNode;
var departments = (from d in lstStaff
                   where !string.IsNullOrEmpty(d.DepartmentName) 
                select new { d.DeptId, d.DepartmentName })
                .Distinct();

foreach (var d in departments)
{
    //add department node
    deptNode = new RadTreeNode()
    {
        Value = d.DeptId,
        Text = d.DepartmentName
    };
    tvwDepartmentCases.Nodes.Add(deptNode);

    //add staff nodes to department node
    var staffs = lstStaff
                    .ToList()
                    .Where(x => x.DeptId == d.DeptId);

    foreach (var s in staffs)
    {
        staffNode = new RadTreeNode()
        {
            Value = s.StaffID,
            Text = s.StaffName
        };
        deptNode.Nodes.Add(staffNode);
    }
}

Any comments are welcomed. Thanks!

Answer 1

Use the GroupBy operator, it’s easy and looks so much nicer.

var departmentGroups = lstStaff.GroupBy(staff => 
    new { staff.DeptID, staff.DepartmentName });

foreach (var department in departmentGroups)
{
    var deptNode = new RadTreeNode()
    {
        Value = department.Key.DeptID,
        Text = department.Key.DepartmentName
    };

    tvwDepartmentCases.Nodes.Add(deptNode);

    foreach (var staffMember in department)
    {
        var staffNode = new RadTreeNode()
        {
            Value = staffMember.StaffID,
            Text = staffMember.StaffName
        };
        deptNode.Nodes.Add(staffNode);
    }
}

It’s also lower complexity because you don’t need to iterate through the entire collection of lstStaff for each department.