How can I drag a form without caption bar?

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

If I use a standard form, I can drag it using the caption bar. How can I drag a form without caption bar?

 

1.

  Start a new project using File | New Application.

 

2.

  Edit the OnMouseMove event:

 

void __fastcall TForm1::FormMouseMove(TObject *Sender,

    TShiftState Shift, int X, int Y)

{

    // If left mouse button is clicked

    if(Shift.Contains(ssLeft))

    {

        ReleaseCapture();

        Perform(WM_NCLBUTTONDOWN, HTCAPTION, NULL);

    }

}

 

Each time the left mouse button is pressed over the caption bar, the WM_NCLBUTTONDOWN message is posted. You can simulate a caption bar click by sending this message.

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