C#

static void Main(string[] args)
{
  if (args.Length == 2)
    Process.Start("program.exe",
      string.Format("\"{0}\" \"{1}\"", args[0], args[1]);
}

ID  ParentID  Text
--- --------- -----
0   (null)    Node1
1   0         Node1_1
2   0         Node1_2
3   2         Node1_2_1
4   3         Node1_2_1_1

public void BuildTree()
{
  DataSet ds = GetDataSet(); // Method to retrieve the DataSet - made-up as example
  DataRow[] rows = ds.Tables[0].Select("ParentID = NULL");
  treeView1.BeginUpdate(); // Don't update display till done == faster
  for (int i=0; i<rows.Length; i++)
  {
    TreeNode node = new TreeNode();
    node.Text = (string)rows[i]["Text"];
    node.Tag = rows[i]["ID"];
    this.treeView1.Nodes.Add(node);
    BuildSubTree(node, ds);
  }
  treeView1.EndUpdate();
}

private void BuildSubTree(TreeNode parent, DataSet ds)
{
  int id = (int)parent.Tag;
  DataRow[] rows = ds.Tables[0].Select(string.Concat("ParentID = ", id.ToString()));
  for (int i=0; i<rows.Length; i++)
  {
    TreeNode node = new TreeNode();
    node.Text = (string)rows[i]["Text"];
    node.Tag = rows[i]["ID"];
    parent.Nodes.Add(node);
    BuildSubTree(node, ds);
  }
}