在Delphi Designer中保持控件处于最前面

Question

I created a simple design-time component that helps to select and bring to front other components on the same form. (It is more convenient than IDE object tree view when designing full screen forms in a single monitor environment). But in Delphi XE2, I cannot reliably ensure and detect that the helper component itself is on the top. When I select it, the IDE draws 8 blue balls as a marker around it, and it seems to me that those markers are part of the actual top level window.

So, how could I check if a component is selected in the IDE designer?

Answer 1

So, how could I check if a component is selected in the IDE designer?

Create a design-time editor for your component (make sure you implement it in a designtime-only package, not a runtime package), and register it with RegisterComponentEditor() . TComponentEditor has a Designer property to access the Form Designer's IDesigner interface, which has a GetSelections() method:

procedure GetSelections(const List: IDesignerSelections);

IDesignerSelections has Count and Items[] properties, where Items[] returns a TPersistent object. So you can loop through the list looking for your desired component object(s) (all components derive from TPersistent ).

IDesigner also has SelectComponent() and SetSelections() methods, so you can have the Form Designer select other components as needed:

procedure SelectComponent(Instance: TPersistent); overload;
procedure SelectComponent(const ADesignObject: IDesignObject); overload;
procedure SetSelections(const List: IDesignerSelections);