asked on

Generate a treeview

I have a dataset with fields 'son and 'father'.
(root with father=spaces)(likely subdirectory directory)
Do you know any algorithm generate a tree with
this dataset?
Please tell me. Thanks.

rwilson032697

There are some data aware tree views around. Take a look on DSP(http://sunsite.icm.edu.pl/delphi) - there is a search engine.

Cheers,

Raymond.

ASKER CERTIFIED SOLUTION

apaparis

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kretzschmar

hi mathematics,

instead teh table i used, you can do it with a dataset also,

procedure TForm1.Button1Click(Sender: TObject);
var
Found : Boolean;
I : Integer;
t : TTreeNode;
begin
{ Clear Treeview }
while treeview1.Items.count > 0 do treeview1.Items[0].delete;
{ Create a root }
treeview1.Items.Add(treeview1.TopItem,Table1.TableName);
table1.open;
table1.first;
while not(Table1.eof) do
begin
i := 0;
Found := False;

{ Search for Father }

while Not(Found) and (i < TreeView1.Items.Count) do
begin
Found := Table1.FieldByName('Father').AsString = Treeview1.Items[i].Text;
if Not(Found) then inc(i);
end;

If Found then {Father exists, add son }
begin
t := TreeView1.Items.AddChild(TreeView1.Items[i],Table1.FieldByName('Son').AsString);
{ Do Something else with t }
end
else
begin {Father not exists, add Father to root, add son }
t := TreeView1.Items.AddChild(TreeView1.TopItem,Table1.FieldByName('Father').AsString);
{ Do Something else with t }
t := TreeView1.Items.AddChild(t,Table1.FieldByName('Son').AsString);
{ Do Something else with t }
end;
Table1.Next; {Next Record}
end;
table1.Close;
end;

can be optimized, of course

meikl

apaparis

Sorry. This is right

If Id is primary key
and father is pointing to father record

// Body
DataSet = "Select * from table where father = 0 order by Id"
while not eof begin
currentNode := <-- append current rec to tree root
appendSubtree(Id, CurrentNode)
DataSet.Next
end

Procedure appendSubtree(AnId, ANode)
SubDataSet := "Select * from Table Where Father = " + IntToStr(AnId)

While Not SubDataSet.Eof Begin
SubTreeNode := <-- append current rec under ANode
AppendSubTree (Id, SubTreeNode)
SubDataSet.Next
End
End