[SOLVED] TreevView - Remove All Nodes

[pixelink]

I found this page on the wiki...
https://wiki.lazarus.freepascal.org/TTreeView

I used the code suggested to delete all nodes.
Get an error. saying...

TreeView1.Items.Delete(Node)  (--> NOT FOUND)

And yet, my control's name is TreeView1

Why does it say not found?

Obviously wiki is missing some code.

Code: Pascal  [Select][+][-]

1. //A procedure to recursively delete nodes
2. procedure DeleteNode(Node:TTreeNode);
3. begin
4.   while Node.HasChildren do
5.     begin
6.        DeleteNode(node.GetLastChild);
7.        TreeView1.Items.Delete(Node); //<-- ERROR
8.     end;
9. end;
10.  
11. procedure TForm1.mnuNewClick(Sender: TObject);
12. var
13.    Node:TTreeNode;
14. begin
15.   if TreeView1.Selected = nil then
16.     exit;
17.  
18.   //if selected node has child nodes, first ask for confirmation
19.   if treeview1.Selected.HasChildren then
20.     if messagedlg( 'Delete node and all children ?',mtConfirmation, [mbYes,mbNo],0 ) <> mrYes then
21.       exit;
22.  
23.   DeleteNode(TreeView1.Selected);
24.  
25.   //add a new root node - I added this code
26.   Treeview1.Items.Add (nil,'Root Node');
27.  
28. end;
29.  

Thanks

end;

[pixelink]

I hat that when that happens...
 I post a thread then figure it out.

I needed to insert Form1.TreeView1
Because it in a procedure.

Code that works now...

Code: Pascal  [Select][+][-]

1.  
2. //A procedure to recursively delete nodes
3. procedure TForm1.DeleteNode(Node:TTreeNode);
4. begin
5.   while Node.HasChildren do
6.     begin
7.        DeleteNode(node.GetLastChild);
8.        Form1.TreeView1.Items.Delete(Node); //<-- ERROR
9.     end;
10. end;
11.  
12. procedure TForm1.mnuNewClick(Sender: TObject);
13. var
14.    Node:TTreeNode;
15. begin
16.   if TreeView1.Selected = nil then
17.     exit;
18.  
19.   //if selected node has child nodes, first ask for confirmation
20.   if treeview1.Selected.HasChildren then
21.     if messagedlg( 'Delete node and all children ?',mtConfirmation, [mbYes,mbNo],0 ) <> mrYes then
22.       exit;
23.  
24.   DeleteNode(TreeView1.Selected);
25.  
26.   //add a new root node - I added this code
27.   Treeview1.Items.Add (nil,'Root Node');
28.  
29. end;
30.  
31.  

[lucamar]

Making the proc a method of form1 should suffice, since then TreeView1 is in scope:

Code: Pascal  [Select][+][-]

1.  
2. //A procedure to recursively delete nodes
3. procedure TForm1.DeleteNode(Node:TTreeNode);
4. begin
5.   while Node.HasChildren do
6.     begin
7.        DeleteNode(node.GetLastChild);
8.        TreeView1.Items.Delete(Node); //<-- ERROR
9.     end;
10. end;
11.  
12. procedure TForm1.mnuNewClick(Sender: TObject);
13. var
14.    Node:TTreeNode;
15. begin
16.   if TreeView1.Selected = nil then
17.     exit;
18.  
19.   //if selected node has child nodes, first ask for confirmation
20.   if treeview1.Selected.HasChildren then
21.     if messagedlg( 'Delete node and all children ?',mtConfirmation, [mbYes,mbNo],0 ) <> mrYes then
22.       exit;
23.  
24.   DeleteNode(TreeView1.Selected);
25.  
26.   //add a new root node - I added this code
27.   Treeview1.Items.Add (nil,'Root Node');
28.  
29. end;

[wp]

I found this page on the wiki...
https://wiki.lazarus.freepascal.org/TTreeView

I used the code suggested to delete all nodes.
Get an error. saying...

TreeView1.Items.Delete(Node)  (--> NOT FOUND)

And yet, my control's name is TreeView1

Why does it say not found?

Obviously wiki is missing some code.

This is the wiki code:

Code: Pascal  [Select][+][-]

1. procedure TForm1.Button2Click(Sender: TObject);
2.  
3.     //A procedure to recursively delete nodes
4.   procedure DeleteNode(Node:TTreeNode);
5.   begin
6.     while Node.HasChildren do
7.       DeleteNode(node.GetLastChild);
8.     TreeView1.Items.Delete(Node) ;
9.   end;
10.  
11. begin
12.   if TreeView1.Selected = nil then
13.     exit;
14.  
15.     //if selected node has child nodes, first ask for confirmation
16.   if treeview1.Selected.HasChildren then
17.     if messagedlg( 'Delete node and all children ?',mtConfirmation, [mbYes,mbNo],0 ) <> mrYes then
18.       exit;
19.   DeleteNode(TreeView1.Selected);
20. end;

You see here that the procedure "DeleteNode" is nested in TForm1.Button2Click. This means that it lives inside TForm1 like any other TForm1 method and knows everything about TForm1 and its components. You, however, made an non-method procedure out of it, and this removed all the context.

The wiki is fully correct here.