Question

Coming from Win32, I am having bit of an issue or a problem trying to work with treeview for .NET. I have searched online, msdn library and stackoverflow and none seem to help me.

Could someone, please, show me how you can use Treeview to create node, create childnode, set data or object, retrieve object, check its level, etc…

Example code would be greatly appreciated. Thank you.

Answer 1

1) Create a root Node

use the Nodes.Add method

treeView1.Nodes.Add('A Node');

2) Create a Child Node, get the instance to the parent node and uses the Nodes.Add

Node.Nodes.Add('A Child Node');

3) To store an object in anode use the Tag property of the Node

Node.Tag:=MyObj;

4) To Retrieve the object use the tag property and cast the value.

MyObj2:= TMyObject(Node.Tag);

5) to get the level, chek the Level property of the node.

Check this simple code :

Var
  Node     : TreeNode;  
  MyObj    : TMyObject; 
  MyObj2   : TMyObject; 
begin
  Node:=treeView1.Nodes.Add('A Node'); //add a root node 
  Node.Text:= String.Format('{0} in level {1}',Node.Text,Node.Level);

    Node.Nodes.Add('A Child Node');
    Node.Nodes.Add('Another Child Node');
  Node:=treeView1.Nodes.Add('Another Node');

  MyObj:=New TMyObject;
  MyObj.Foo:='Hello';
  Node.Tag:=MyObj;//set the object



  MyObj2:= TMyObject(Node.Tag); //get the assigned object
  MessageBox.Show(MyObj2.Foo);

end;