winapi - C++Builder: Create a TForm with BorderStyle bsNone that is nevertheless movable and resizable

Question

I'd like to have a TForm with BorderStyle = bsNone (no borders, no caption), which is nevertheless resizable and movable. I already figured out how to do the resizable part, but I'm stuck with getting it movable.

/**
*   Overrides standard CreateParams method to create a TForm with BorderStyle
*    bsNone but is nevertheless movable and resizable
**/
void __fastcall CreateParams(TCreateParams &Params)
{
    BorderStyle = bsNone;
    TForm::CreateParams(Params);
    //set flag WS_EX_STATICEDGE
    //for more details on this flag, see http://msdn.microsoft.com/en-us/library/ms632680(v=vs.85).aspx
    Params.ExStyle = Params.ExStyle ^ 0x00020000L;
    //set flag WS_SIZEBOX
    //for more details on this flag, see http://msdn.microsoft.com/en-us/library/ff700543(v=VS.85).aspx
    Params.Style = Params.Style ^ 0x00040000L;
}

It's probably only a matter of finding the correct flags. Any ideas?

Answer 1

Try to place this code to Form OnMouseDown event handler:

ReleaseCapture();
this->Perform(WM_SYSCOMMAND, 0xF012, 0);