Create and Manage Modal and Modeless forms in a DLL (Views: 699)
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Problem/Question/Abstract: Displaying and using forms from a DLL can be difficult if you don't know the way. Fortunately enough, Delphi is quite flexible and the managing forms from a DLL is quite easy. Answer: The first thing you will need a Handle to the application’s main window. Assuming that the application is running on top, you can get the window’s handle using GetActiveWindow, like this: MainApplicationHandle := GetActiveWindow; In order to be able to take advantage of Delphi’s window controlling features, however, you need a window control, not a window handle. You can get a window control uising FindControl (Controls Unit) fWinControl := FindControl(MainApplicationHandle); fWinControl is assumed to be of TwinControl type.. I have found it useful to create the Modal (or modeless window) since the begiinning: MyForm := TMyForm.create(fWinControl); The three items can be placed confortably in the initialization section of the DLL: MainApplicationHandle := GetActiveWindow; fWinControl := FindControl(MainApplicationHandle); MyForm := TMyForm.create(fWinControl); Finally, when you need the Form, you just show it, but be carfeul to redraw it if something changed within it: MyForm.Repaint; winresult := MyForm.showmodal (winresult is defined to be of typo longint) You just have to be sure that your form includes wither buttons that produce a modal result (by setting ModalResult to something else than mrNone) If you’d rather prefer a modeless window (for example, to display a progress bar) , you can use the following approach: MyForm.Visible := true; while {some condition set} do begin {change something in the window} MyForm.repaint; end; MyForm.Hide; |