TdxGanttControlTaskStartDragEvent Type

Performs a set of actions before a user moves a task in the sheet.

Declaration

TdxGanttControlTaskStartDragEvent = 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 task that is about to be rearranged.
AAllow	Boolean	If True, a user can rearrange a task row in the sheet with the mouse. If False, the operation is prohibited.

Remarks

You can open the Features Demo and modify its code. The code snippet below shows how you can handle the OnTaskStartDrag event to prevent a user from task rearrangement:

Delphi

procedure TFeaturesDemoMainForm.GanttControlViewChartOptionsSheetTaskStartDrag(
  Sender: TObject; ATask: TdxGanttControlTask; var Allow: Boolean);
begin
  inherited;
  Allow := not ATask.Summary;
end; 

C++

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