[Delphi] open text files in one application
- by Remus Rigo
hi all
I want to write an text editor and to assign the txt files to it. My problem is that I want to have only one instance running and when a new file is opened to send the filename to the first app that is already running... (I want to do this using mutex). Here is a small test
DPR looks like this
uses
Windows, Messages, SysUtils,
Forms,
wndMain in 'wndMain.pas' {frmMain};
{$R *.res}
var
PrevWindow : HWND;
S : string;
CData : TCopyDataStruct;
begin
PrevWindow := 0;
if OpenMutex(MUTEX_ALL_ACCESS, False, 'MyMutex') <> 0 then
begin
repeat
PrevWindow:=FindWindow('TfrmMain', nil);
until PrevWindow<>Application.Handle;
if IsWindow(PrevWindow) then
begin
SendMessage(PrevWindow, WM_SYSCOMMAND, SC_RESTORE, 0);
BringWindowToTop(PrevWindow);
SetForegroundWindow(PrevWindow);
if FileExists(ParamStr(1)) then
begin
S:=ParamStr(1);
CData.dwData:=0;
CData.lpData:=PChar(S);
CData.cbData:=1+Length(S);
SendMessage(PrevWindow, WM_COPYDATA, 0, DWORD(@CData) );
end;
end;
end
else
CreateMutex(nil, False, 'MyMutex');
Application.Initialize;
Application.CreateForm(TfrmMain, frmMain);
Application.Run;
end.
PAS:
type TfrmMain = class(TForm)
memo: TMemo;
private
procedure WMCopyData ( var msg : TWMCopyData ) ; message WM_COPYDATA;
public
procedure OpenFile(f : String);
end;
var
frmMain: TfrmMain;
implementation
{$R *.dfm}
procedure TfrmMain.WMCopyData ( var msg : TWMCopyData ) ;
var
f : String;
begin
f:=PChar(msg.CopyDataStruct.lpData);
//ShowMessage(f);
OpenFile(f);
end;
procedure TfrmMain.OpenFile(f : String);
begin
memo.Clear;
memo.Lines.LoadFromFile(f);
Caption:=f;
end;
this code should be ok, but if i want to open a text file (from the second app), the first app receives a message like this:
thanks
