Print TreeView in Delphi [duplicate] - delphi

Question

I created an application that goes out and scans every computer and populates a TreeView with Hardware, Software and updates/hotfixes information:
The problem I’m having is with printing, how do you automatically expand the treeview and sends the results of the selected computer to the printer? The method I am currently using involves sending the contents to a canvas (BMP) and then send it to the printer but that does not capture the whole treeview only whatever is being displayed on the screen. Any advice? Thank you so much.

Answer 1

The problem with printing the TTreeView is that the part that isn't visible has nothing to be drawn. (Windows draws only the visible portion of the control, so when you use PrintTo or the API PrintWindow function, it only has the visible nodes available to print - the non-displayed content hasn't yet been drawn and therefore can't be printed.)
If a tabular layout works (no lines, just indented levels), the easiest way is to create text and put it in a hidden TRichEdit, and then let the TRichEdit.Print handle the output. Here's an example:
// File->New->VCL Forms Application, then
// Drop a TTreeView and a TButton on the form.
// Add the following for the FormCreate (to create the treeview content)
// and button click handlers, and the following procedure to create
// the text content:
procedure TreeToText(const Tree: TTreeView; const RichEdit: TRichEdit);
var
Node: TTreeNode;
Indent: Integer;
Padding: string;
const
LevelIndent = 4;
begin
RichEdit.Clear;
Node := Tree.Items.GetFirstNode;
while Node <> nil do
begin
Padding := StringOfChar(#32, Node.Level * LevelIndent);
RichEdit.Lines.Add(Padding + Node.Text);
Node := Node.GetNext;
end;
end;
procedure TForm1.Button1Click(Sender: TObject);
var
HideForm: TForm;
HideEdit: TRichEdit;
begin
HideForm := TForm.Create(nil);
try
HideEdit := TRichEdit.Create(HideForm);
HideEdit.Parent := HideForm;
TreeToText(TreeView1, HideEdit);
HideEdit.Print('Printed TreeView Text');
finally
HideForm.Free;
end;
end;
procedure TForm3.FormCreate(Sender: TObject);
var
i, j: Integer;
RootNode, ChildNode: TTreeNode;
begin
RootNode := TreeView1.Items.AddChild(nil, 'Root');
for i := 1 to 6 do
begin
ChildNode := TreeView1.Items.AddChild(RootNode, Format('Root node %d', [i]));
for j := 1 to 4 do
TreeView1.Items.AddChild(ChildNode, Format('Child node %d', [j]));
end;
end;