TdxGanttControlTaskStartLinkEvent Type

Performs a set of actions before a user drags and drops a dependency from one task to another with the mouse.

Declaration

TdxGanttControlTaskStartLinkEvent = procedure(Sender: TObject; ATask: TdxGanttControlTask; var AAllow: Boolean) of object;

Parameters

Name	Type	Description
Sender	TObject	The Chart View that raised the event.
ATask	TdxGanttControlTask	The predecessor task.
AAllow	Boolean	If True, a user can move the mouse pointer from the selected task to another task (while holding the left mouse button) to link them. If False, the operation is prohibited.

Remarks

You can open the Features Demo and modify its code. Handle the OnTaskStartLink event and use the following code snippet to prevent a user from linking a summary task to any task:

Delphi

procedure TFeaturesDemoMainForm.GanttControlViewChartTaskStartLink(Sender: TObject;
  ATask: TdxGanttControlTask; var AAllow: Boolean);
begin
    AAllow := not ATask.Summary;
end;

C++

void __fastcall TFeaturesDemoMainForm::GanttControlViewChartTaskStartLink(TObject *Sender,
          TdxGanttControlTask *ATask, bool &AAllow)
{
  AAllow = !(ATask->Summary);
}