Question

I need to add functionality to copy a rectangular selection of nodes and columns, but I can’t find any way to actually select multiple columns in a Virtual Treeview (beside toFullRowSelect).

Am I just missing something? And if not, is there a descendant out there with grid-like multicolumn select support?

Answer 1

So after some testing I came up with the following, thanks DiGi for the extra push. DrawSelection won’t work with this solution so it needs to be disabled. Since I don’t think I’ll need to do this again soon I didn’t write a descendant.

Set toDisableDrawSelection, toExtendedFocus and toMultiSelect to True.

Declare the following variables/properties somewhere suitable:

StartSelectedColumn: integer; FirstSelectedColumn: integer; LastSelectedColumn: integer; Selecting: boolean; 

Update the following events:

OnKeyDown

if (not Selecting) and (Key = VK_SHIFT) then begin   StartSelectedColumn := vtMain.FocusedColumn;   FirstSelectedColumn := StartSelectedColumn;   LastSelectedColumn := StartSelectedColumn;   Selecting := true; end; 

OnKeyUp

if Key = VK_SHIFT then   Selecting := false; 

OnFocusChanged

if Selecting then begin   if column < StartSelectedColumn then   begin     FirstSelectedColumn := column;     LastSelectedColumn := StartSelectedColumn;   end   else if column > StartSelectedColumn then   begin     FirstSelectedColumn := StartSelectedColumn;     LastSelectedColumn := column   end   else   begin     FirstSelectedColumn := column;     LastSelectedColumn := column;   end; end else begin   StartSelectedColumn := column;   FirstSelectedColumn := column;   LastSelectedColumn := column; end; 

OnBeforeCellPaint

if vtMain.Selected[node] and InRange(column, FirstSelectedColumn, LastSelectedColumn) then begin   if vtMain.Focused then     TargetCanvas.Brush.Color := vtMain.Colors.FocusedSelectionColor   else     TargetCanvas.Brush.Color := vtMain.Colors.UnfocusedSelectionColor;   TargetCanvas.Brush.Style := bsSolid;   TargetCanvas.FillRect(CellRect); end; 

OnPaintText

if vtMain.Selected[node] and InRange(column, FirstSelectedColumn, LastSelectedColumn) then begin   if vtMain.Focused then     TargetCanvas.Font.Color := clHighlightText   else     TargetCanvas.Font.Color := vtMain.Font.Color; end;