C#

private void ThreadingGroups()
{
    Thread TsGroups = new Thread(ThreadGroups);
    TsGroups.Start();
}

private void ThreadGroups()
{
    DataTable dt = DOCTemp.GetGroups();
    DataRow dr = dt.NewRow();
    dr[0] = "";
    dr[1] = "Default";
    dt.Rows.InsertAt(dr, 0);
    frmTemplateManager.treeView1.Nodes.Clear();
    for (int i = 0; i < dt.Rows.Count; i++)
    {
        TemplateManagerTreeView(dt.Rows[i]["id"].ToString(), dt.Rows[i]["name"].ToString());
    }
}

private void TemplateManagerTreeView(string id, string name)
{
    frmTemplateManager.treeView1.Nodes.Add(id.ToString(), name.ToString());
}

WITH cte1 (LastName, EmployeeID, Manager, ManagerID, Level)
AS
(
	SELECT e1.lastName, e1.employeeID, e2.LastName, e1.ReportsTo, 0
	FROM Employees e1 LEFT JOIN employees e2 on e1.ReportsTo = e2.EmployeeID
	WHERE e1.ReportsTo IS NULL
	
	UNION ALL
	
	SELECT e1.lastName, e1.employeeID, c.LastName, e1.ReportsTo, Level + 1
	FROM Employees e1 JOIN cte1 c ON e1.ReportsTo = c.EmployeeID		
)
SELECT * FROM cte1

struct Node
{
  unsafe { public Node* parentNode; }
  public int someData;
}

class SomeClass
{
  Node[] nodeArray = new Node[2];
  Node[] otherNodeArray = new Node[1];
  
  void LinkEmUp()
  {
    unsafe
    {  
      nodeArray[0].parentNode = &nodeArray[1];
      otherNodeArray[0].parentNode = &nodeArray[0];
    }
  }
}

class SomeClass
{
  public Node[] nodeArray = new Node[2];
  public Node[] otherNodeArray = new Node[1];
  
  public void LinkEmUp()
  {
    unsafe
    {  
      nodeArray[0].parentNode = &nodeArray[1];
      otherNodeArray[0].parentNode = &nodeArray[0];
    }
  }
}

unsafe static void Main()
{
  SomeClass c = new SomeClass();
  
  //pin SomeClass c and its member arrays, after leaving the scope of the fixed statement
  //the entire thing falls apart, the pointers the arrays are not used, there only to satisfy the requirements of C#
  fixed(Node* _temp = &c.nodeArray[0], __temp = &c.otherNodeAray[0])
  {
    c.LinkEmUp();
    //work with object, after leaving object is useless
    ...
  }
}