How can I drag items between two ListBoxes?

Applies To: C++Builder 1 or higher
Category: Knowledge Base

1.

  Start a new project using File | New Application.

 

2.

  Add two (2) ListBoxes. Set the OnMouseDown, OnDragOver

      and OnDragDrop events of both of them to:

 

void __fastcall TForm1::ListBox1MouseDown(TObject *Sender,

    TMouseButton Button, TShiftState Shift, int X, int Y)

{

    if(Button == mbLeft)

    {

        TListBox *list = (TListBox *)Sender;

        if(list->ItemAtPos(Point(X, Y), true) >= 0)

            list->BeginDrag(false, -1);

    }

}

 

void __fastcall TForm1::ListBox1DragOver(TObject *Sender, TObject

    *Source, int X, int Y, TDragState State, bool &Accept)

{

    if(Source->InheritsFrom(__classid(TListBox)))

        Accept = true;

}

 

void __fastcall TForm1::ListBox1DragDrop(TObject *Sender, TObject

    *Source, int X, int Y)

{

    if(Source->InheritsFrom(__classid(TListBox)))

    {

        TListBox *listsender = (TListBox *)Sender;

        TListBox *listsource = (TListBox *)Source;

 

        listsender->Items->Add(listsource->Items->Strings

            [listsource->ItemIndex]);

        listsource->Items->Delete(listsource->ItemIndex);

    }

}

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