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Posts Tagged ‘vcl’

How to Clear Multiple Edits Without Refering to Them One by One

December 15th, 1999 m3Rlin No comments

Let’s say you have a data entry form or a MP3 ID3 tag editor form. The user clicks the “Clear” button. The more edit controls you have the less you want to write the code to clear them :-) Well, here’s a better idea:

procedure TMainForm.btnClear(Sender: TObject);
var
  iI: Integer;
begin
  for iI := 0 to ComponentCount - 1 do
    if (Components[iI] is TEdit) then
      TEdit(Components[iI]).Clear;
end;

If you want to exclude a edit control from being cleared use this:
!!Note: The name check must be after the VCL class check.

if (Components[iI] is TEdit) and (TEdit(Components[iI].Name <> 'edDontClear')) then
  TEdit(Components[iI]).Text := '';

How to Determine the Screen Resolution

December 15th, 1999 m3Rlin No comments

There are two ways to determine the screen’s height and width.

1) Use the global Screen variable.

uses
  Forms;
...
  Screen.Height { Screen height in pixels }
  Screen.Width  { Screen width in pixels  }
...

2) Use the Windows API GetSystemMetrics() function. This function can be useful in applications that don’t use the VCL like console applications.

uses
  Windows;
...
  GetSystemMetric(SM_CXSCREEN) { Screen height in pixels }
  GetSystemMetric(SM_CYSCREEN) { Screen width in pixels  }
...