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    <p><strong><em>1. Is there a way to use VirtualTreeView for a master / detail grid view ?</em></strong></p> <p>No, there is no such feature available at this time and IMHO won't be, since that would involve a very big intervention to an existing code.</p> <p><strong><em>2. How to create fully functional header for a child node detail grid view ?</em></strong></p> <p>Considering few ways, how to simulate header look and behavior for child nodes I've found useful to use nested tree views for a detail grid view. This brings you the separateness for your detail data and allows you to minimize the whole simulation to positioning of the nested tree view into a child node's rectangle.</p> <p><strong><em>2.1. Startup project</em></strong></p> <p>In the following project I'm trying to show how complicated could be implement such an easy task like the positioning of a control inside of a child node could be (without involving the original VirtualTree code). Take it just as a startup project, not as a final solution.</p> <p><strong><em>2.2. Known issues &amp; limitations:</em></strong></p> <ul> <li>this project was written and tested to use only one child per root node, so don't be surprised with a behavior when you exceed this limit, because this was not designed nor even tested for</li> <li>when a double click column resize of a main tree animates the column resize, the nested tree views are overdrawn with lines when the canvas is being scrolled by the ScrollDC function</li> <li>to keep the VirtualTree code without changing I've overrided the method for scroll bars updating. It is used to update nested tree views bounds whenever the scrollbars needs to be updated</li> <li>current <code>OnExpanded</code> implementation fires the event before the range and scroll positions are fixed, what makes the code more complicated and with a big weakness - the bounds of a detail tree view are updated after the tree is shown, what can be sometimes visible</li> </ul> <p><strong><em>2.3. Project code</em></strong></p> <p>It was written and tested in Delphi 2009 with respect to use in Delphi 7. For commented version of a next code <a href="https://stackoverflow.com/revisions/12188882/1"><code>follow this link</code></a>:</p> <p><strong><em>Unit1.pas</em></strong></p> <pre><code>unit Unit1; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, VirtualTrees; type TVTScrollBarsUpdateEvent = procedure(Sender: TBaseVirtualTree; DoRepaint: Boolean) of object; TVirtualStringTree = class(VirtualTrees.TVirtualStringTree) private FOnUpdateScrollBars: TVTScrollBarsUpdateEvent; public procedure UpdateScrollBars(DoRepaint: Boolean); override; published property OnUpdateScrollBars: TVTScrollBarsUpdateEvent read FOnUpdateScrollBars write FOnUpdateScrollBars; end; type PNodeSubTree = ^TNodeSubTree; TNodeSubTree = class FChildTree: TVirtualStringTree; end; type TForm1 = class(TForm) Button1: TButton; VirtualStringTree1: TVirtualStringTree; procedure FormCreate(Sender: TObject); procedure Button1Click(Sender: TObject); procedure VirtualStringTree1AfterAutoFitColumns(Sender: TVTHeader); procedure VirtualStringTree1BeforeDrawTreeLine(Sender: TBaseVirtualTree; Node: PVirtualNode; Level: Integer; var PosX: Integer); procedure VirtualStringTree1Collapsed(Sender: TBaseVirtualTree; Node: PVirtualNode); procedure VirtualStringTree1ColumnResize(Sender: TVTHeader; Column: TColumnIndex); procedure VirtualStringTree1Expanded(Sender: TBaseVirtualTree; Node: PVirtualNode); procedure VirtualStringTree1FocusChanging(Sender: TBaseVirtualTree; OldNode, NewNode: PVirtualNode; OldColumn, NewColumn: TColumnIndex; var Allowed: Boolean); procedure VirtualStringTree1FreeNode(Sender: TBaseVirtualTree; Node: PVirtualNode); procedure VirtualStringTree1MeasureItem(Sender: TBaseVirtualTree; TargetCanvas: TCanvas; Node: PVirtualNode; var NodeHeight: Integer); private procedure InvalidateSubTrees(Tree: TBaseVirtualTree); procedure ResizeSubTrees(Tree: TBaseVirtualTree); procedure UpdateSubTreeBounds(Tree: TBaseVirtualTree; Node: PVirtualNode); procedure OnUpdateScrollBars(Sender: TBaseVirtualTree; DoRepaint: Boolean); public { Public declarations } end; var Form1: TForm1; implementation {$R *.dfm} { TVirtualStringTree } procedure TVirtualStringTree.UpdateScrollBars(DoRepaint: Boolean); begin inherited; if HandleAllocated and Assigned(FOnUpdateScrollBars) then FOnUpdateScrollBars(Self, DoRepaint); end; { TForm1 } procedure TForm1.FormCreate(Sender: TObject); begin ReportMemoryLeaksOnShutdown := True; VirtualStringTree1.NodeDataSize := SizeOf(TNodeSubTree); VirtualStringTree1.OnUpdateScrollBars := OnUpdateScrollBars; end; procedure TForm1.Button1Click(Sender: TObject); var Data: PNodeSubTree; Node: PVirtualNode; begin Node := VirtualStringTree1.AddChild(nil); Node := VirtualStringTree1.AddChild(Node); VirtualStringTree1.InitNode(Node); Data := VirtualStringTree1.GetNodeData(Node); Data^ := TNodeSubTree.Create; Data^.FChildTree := TVirtualStringTree.Create(nil); with Data.FChildTree do begin Visible := False; Parent := VirtualStringTree1; Height := 150; DefaultNodeHeight := 21; Header.AutoSizeIndex := 0; Header.Font.Charset := DEFAULT_CHARSET; Header.Font.Color := clWindowText; Header.Font.Height := -11; Header.Font.Name := 'Tahoma'; Header.Font.Style := []; Header.Height := 21; Header.Options := [hoColumnResize, hoDrag, hoShowSortGlyphs, hoVisible]; TabStop := False; with Header.Columns.Add do begin Width := 100; Text := 'Header item 1'; end; with Header.Columns.Add do begin Width := 100; Text := 'Header item 2'; end; end; end; procedure TForm1.VirtualStringTree1AfterAutoFitColumns(Sender: TVTHeader); begin InvalidateSubTrees(Sender.Treeview); end; procedure TForm1.VirtualStringTree1BeforeDrawTreeLine(Sender: TBaseVirtualTree; Node: PVirtualNode; Level: Integer; var PosX: Integer); begin if Level = 1 then PosX := 0; end; procedure TForm1.VirtualStringTree1Collapsed(Sender: TBaseVirtualTree; Node: PVirtualNode); var Data: PNodeSubTree; begin Data := VirtualStringTree1.GetNodeData(Node.FirstChild); if Assigned(Data^) and Assigned(Data^.FChildTree) then Data^.FChildTree.Visible := False; end; procedure TForm1.VirtualStringTree1ColumnResize(Sender: TVTHeader; Column: TColumnIndex); begin ResizeSubTrees(Sender.Treeview); end; procedure TForm1.VirtualStringTree1Expanded(Sender: TBaseVirtualTree; Node: PVirtualNode); var Data: PNodeSubTree; begin Data := VirtualStringTree1.GetNodeData(Node.FirstChild); if Assigned(Data^) and Assigned(Data^.FChildTree) then Data^.FChildTree.Visible := True; end; procedure TForm1.VirtualStringTree1FocusChanging(Sender: TBaseVirtualTree; OldNode, NewNode: PVirtualNode; OldColumn, NewColumn: TColumnIndex; var Allowed: Boolean); begin if Sender.GetNodeLevel(NewNode) = 1 then begin Allowed := False; if Sender.AbsoluteIndex(OldNode) &gt; Sender.AbsoluteIndex(NewNode) then Sender.FocusedNode := Sender.GetPreviousSibling(OldNode) else if OldNode &lt;&gt; Sender.GetLastChild(nil) then Sender.FocusedNode := Sender.GetNextSibling(OldNode) else Sender.FocusedNode := OldNode; end; end; procedure TForm1.VirtualStringTree1FreeNode(Sender: TBaseVirtualTree; Node: PVirtualNode); var Data: PNodeSubTree; begin Data := VirtualStringTree1.GetNodeData(Node); if Assigned(Data^) then begin if Assigned(Data^.FChildTree) then Data^.FChildTree.Free; Data^.Free; end; end; procedure TForm1.VirtualStringTree1MeasureItem(Sender: TBaseVirtualTree; TargetCanvas: TCanvas; Node: PVirtualNode; var NodeHeight: Integer); var Data: PNodeSubTree; begin if VirtualStringTree1.GetNodeLevel(Node) = 1 then begin Data := VirtualStringTree1.GetNodeData(Node); if Assigned(Data^) and Assigned(Data^.FChildTree) then NodeHeight := Data^.FChildTree.Height + 8; end; end; procedure TForm1.InvalidateSubTrees(Tree: TBaseVirtualTree); var Data: PNodeSubTree; Node: PVirtualNode; begin Node := Tree.GetFirst; while Assigned(Node) do begin if Tree.HasChildren[Node] then begin Data := Tree.GetNodeData(Node.FirstChild); if Assigned(Data^) and Assigned(Data^.FChildTree) then begin Data^.FChildTree.Header.Invalidate(nil); Data^.FChildTree.Invalidate; end; end; Node := Tree.GetNextSibling(Node); end; end; procedure TForm1.ResizeSubTrees(Tree: TBaseVirtualTree); var Node: PVirtualNode; begin Node := Tree.GetFirst; while Assigned(Node) do begin if Tree.HasChildren[Node] then UpdateSubTreeBounds(Tree, Node.FirstChild); Node := Tree.GetNextSibling(Node); end; end; procedure TForm1.UpdateSubTreeBounds(Tree: TBaseVirtualTree; Node: PVirtualNode); var R: TRect; Data: PNodeSubTree; begin if Assigned(Node) then begin Data := Tree.GetNodeData(Node); if Assigned(Data^) and Assigned(Data^.FChildTree) and Data^.FChildTree.Visible then begin R := Tree.GetDisplayRect(Node, -1, False, True); R.Left := R.Left + (Tree as TVirtualStringTree).Indent; R.Top := R.Top + 4; R.Right := R.Right - 8; R.Bottom := R.Bottom - 4; Data^.FChildTree.BoundsRect := R; end; end; end; procedure TForm1.OnUpdateScrollBars(Sender: TBaseVirtualTree; DoRepaint: Boolean); begin ResizeSubTrees(Sender); end; end. </code></pre> <p><strong><em>Unit1.dfm</em></strong></p> <pre><code>object Form1: TForm1 Left = 0 Top = 0 Caption = 'Form1' ClientHeight = 282 ClientWidth = 468 Color = clBtnFace Font.Charset = DEFAULT_CHARSET Font.Color = clWindowText Font.Height = -11 Font.Name = 'Tahoma' Font.Style = [] OldCreateOrder = False OnCreate = FormCreate DesignSize = ( 468 282) PixelsPerInch = 96 TextHeight = 13 object VirtualStringTree1: TVirtualStringTree Left = 8 Top = 8 Width = 371 Height = 266 Anchors = [akLeft, akTop, akRight, akBottom] Header.AutoSizeIndex = 0 Header.Font.Charset = DEFAULT_CHARSET Header.Font.Color = clWindowText Header.Font.Height = -11 Header.Font.Name = 'Tahoma' Header.Font.Style = [] Header.Height = 21 Header.Options = [hoColumnResize, hoDblClickResize, hoDrag, hoShowSortGlyphs, hoVisible] TabOrder = 0 TreeOptions.MiscOptions = [toVariableNodeHeight] OnAfterAutoFitColumns = VirtualStringTree1AfterAutoFitColumns OnBeforeDrawTreeLine = VirtualStringTree1BeforeDrawTreeLine OnCollapsed = VirtualStringTree1Collapsed OnColumnResize = VirtualStringTree1ColumnResize OnExpanded = VirtualStringTree1Expanded OnFocusChanging = VirtualStringTree1FocusChanging OnFreeNode = VirtualStringTree1FreeNode OnMeasureItem = VirtualStringTree1MeasureItem ExplicitWidth = 581 ExplicitHeight = 326 Columns = &lt; item Position = 0 Width = 75 WideText = 'Column 1' end item Position = 1 Width = 75 WideText = 'Column 2' end item Position = 2 Width = 75 WideText = 'Column 3' end&gt; end object Button1: TButton Left = 385 Top = 8 Width = 75 Height = 25 Anchors = [akTop, akRight] Caption = 'Button1' TabOrder = 1 OnClick = Button1Click ExplicitLeft = 595 end end </code></pre> <p><strong><em>2.4. Screenshot</em></strong></p> <p><img src="https://i.stack.imgur.com/1sj1K.png" alt="enter image description here"></p>
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    1. COThis is the most impressive code I have ever seen in my life! Wish I could give you more rep points for this!
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      1. USBenjamin Weiss
 

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