[SOLVED] Placing Opening Code in EXE for Opening Associate Files

[pixelink]

Hi,


I am making a "reader" app.
After a user associates a file type in Windows and they double click it to open it...

Where do I place my Opening code so that when the user double-clicks on file type my app it will run the opening file procedure?

Where do I put my code? FormCreate, Active or Show?

Thanks

[Ally]

Code: Pascal  [Select][+][-]

1. procedure TfrmFrmMain.FormShow(Sender: TObject);
2. begin
3.   if (ParamCount > 0) and (FileExists(ParamStrUTF8(1))) and (UTF8LowerCase(ExtractFileExt(ParamStrUTF8(1))) = '.xyz') then
4.     OpenMyFile(ParamStrUTF8(1));
5. end;
6.  

[lucamar]

The OnCreate handler of the main form is more or less the"standard" place, because normally it's called only once at the start of the program.

I have seen people put it (conditionally) in the OnShow event and I myself use the OnActivate handler when I have first to make sure the form and controls are completely initialized before loading any file.

But most of the times, the OnCreate handler is the proper one.

Code: Pascal  [Select][+][-]

1. procedure TfrmFrmMain.FormShow(Sender: TObject);
2. begin
3.   if (ParamCount > 0) and (FileExists(ParamStrUTF8(1))) and (UTF8LowerCase(ExtractFileExt(ParamStrUTF8(1))) = '.xyz') then
4.     OpenMyFile(ParamStrUTF8(1));
5. end;
6.  

The problem with that code is that the OnShow event is trigered on many conditions, not just on starting the program, so you keep (re-)loading the parameters at odd moments during the application run-time.

If for whatever reason you want to make it in OnShow, use something like:

Code: Pascal  [Select][+][-]

1. procedure TfrmFrmMain.FormCreate(Sender: TObject);
2. begin
3.   ParamsLoaded := False;
4. end;
5.  
6. procedure TfrmFrmMain.FormShow(Sender: TObject);
7. begin
8.   if not ParamsLoaded then begin
9.     if (ParamCount > 0) and (FileExists(ParamStrUTF8(1))) and (UTF8LowerCase(ExtractFileExt(ParamStrUTF8(1))) = '.xyz') then
10.       OpenMyFile(ParamStrUTF8(1));
11.     ParamsLoaded := True;
12.   end;
13. end;

Or if you use OnShow just for that:

Code: Pascal  [Select][+][-]

1. procedure TfrmFrmMain.FormShow(Sender: TObject);
2. begin
3.   OnShow := Nil; {Make sure it's called only once}
4.   if (ParamCount > 0) and (FileExists(ParamStrUTF8(1))) and (UTF8LowerCase(ExtractFileExt(ParamStrUTF8(1))) = '.xyz') then
5.     OpenMyFile(ParamStrUTF8(1));
6. end;

[pixelink]

Thanks... I will give it a go.

[pixelink]

three things...

I don't know anyhing about this code.

1) I get error with "ParamsLoaded" and "UTF8LowerCase" in the onShow event

What is supposed to be my uses declaration and any var or const declaration?


2) What is my procedure code block supposed to look like?

Code: Pascal  [Select][+][-]

1. procedure TForm1.OpenMyFile(Sender: TObject;);  //procedure TForm1.OpenMyFile(ParamStrUTF8(1));
2. begin
3.        {my code that loads file - see #3 below}
4. end;  
5.  

3) This is the code that woks opening a file using DLG.
Not sure how I pass the file name when opening from an associated file.

Code: Pascal  [Select][+][-]

1. oDlg.Filter:='My File Formats (*.mytxt)|*.mytxt';
2. oDlg.Filename:='';
3.     if oDlg.Execute then
4.        KMemo1.Clear;
5.        fName:=oDlg.Filename;
6.        ext:=ExtractFileExt(oDlg.FileName.ToLower);
7.        if ext = '.mytxt' then
8.              begin
9.                   L := TStringList.Create;
10.                 try
11.                   L.LoadFromFile(fName);
12.                   s := CP1252ToUTF8(L.Text);
13.                   KMemo1.Text := s;
14.                 finally
15.                   L.Free;
16.                 end
17.              end;
18.  
19.  
20.  

[lainz]

like this

Code: Pascal  [Select][+][-]

1. procedure TForm1.OpenMyFile(aFilename:string);
2. var L: TStringList;
3. s: string;
4. begin
5.        if LowerCase(ExtractFileExt(aFilename)) = '.mytxt' then
6.              begin
7.                  KMemo1.Clear;
8.                  L := TStringList.Create;
9.                 try
10.                   L.LoadFromFile(aFilename);
11.                   s := CP1252ToUTF8(L.Text);
12.                   KMemo1.Text := s;
13.                 finally
14.                   L.Free;
15.                 end
16.              end;
17. end;

Code: Pascal  [Select][+][-]

1. OpenMyFile(ParamStrUTF8(1));

then you can replace the dialog function

Code: Pascal  [Select][+][-]

1. oDlg.Filter:='My File Formats (*.mytxt)|*.mytxt';
2. oDlg.Filename:='';
3.     if oDlg.Execute then
4.       OpenMyFile(oDlg.Filename);

[lucamar]

I've attached a small, qucik but rather complete example of how it may be done.

About your questions:

1) I get error with "ParamsLoaded" and "UTF8LowerCase" in the onShow event

ParamsLoaded  was intended to be a field or var that you add to your code. UTF8LowerCase is in the unit lazutf8, of the LazUtils package.

2) What is my procedure code block supposed to look like?

3) This is the code that woks opening a file using DLG.
Not sure how I pass the file name when opening from an associated file.

See the attached example; it shows it rather well (if I can say so myself )

One thing: Instead of a string list my code uses ReadFileToString().

Doing so takes out all the (small) complexity of creating the list, making it parse Text, freeing it, etc. and makes the code a little terser and simpler, but it may look "strange" if you normally use string lists for this.

[pixelink]

I've attached a small, qucik but rather complete example of how it may be done.

About your questions:

1) I get error with "ParamsLoaded" and "UTF8LowerCase" in the onShow event

ParamsLoaded  was intended to be a field or var that you add to your code. UTF8LowerCase is in the unit lazutf8, of the LazUtils package.

2) What is my procedure code block supposed to look like?

3) This is the code that woks opening a file using DLG.
Not sure how I pass the file name when opening from an associated file.

See the attached example; it shows it rather well (if I can say so myself )

One thing: Instead of a string list my code uses ReadFileToString().

Doing so takes out all the (small) complexity of creating the list, making it parse Text, freeing it, etc. and makes the code a little terser and simpler, but it may look "strange" if you normally use string lists for this.

@LUCAMAR
Actually, it does work perfect if I say so myself

You are pretty good at this stuff.

I got a ways to go

THANKS....
I will study it and figure it out so I can finish my app.

[lucamar]

Glad it helped

[pixelink]

I am getting an error.... ReadFileToString not found.

I don't see where this is declared.

[pixelink]

Never mind... figured it out.
Went online to looked it up and I see I forgot the FileUtil uses

[lucamar]

Sorry, I thought that was automatically added? It always is in my projects but I've tweaked so many things ...

What I usually do when that happens is open lhelp and search in the docs. Just to avoid a trip online

Then I also have a kind a series of indexes to the help files made with chmls and filtered through a small utility of mine. That allows me to do a quick grep to know if something is in the docs before opening the CHMs, which can be somewhat slow (lcl.chm being the worst, of course).

But al this is OT, sorry

[pixelink]

Sorry, I thought that was automatically added? It always is in my projects but I've tweaked so many things ...

What I usually do when that happens is open lhelp and search in the docs. Just to avoid a trip online

Then I also have a kind a series of indexes to the help files made with chmls and filtered through a small utility of mine. That allows me to do a quick grep to know if something is in the docs before opening the CHMs, which can be somewhat slow (lcl.chm being the worst, of course).

But al this is OT, sorry

Don't apologize, it was in your sample. I just didn't copy that part.

[lucamar]

Don't apologize, it was in your sample. I just didn't copy that part.

Oh! Ok, that's reasuring 

[pixelink]

Alright....

My end game was to be able to open many different file formats, both known (txt, rtf) and my own proprietary formats which I will making in the future.
Plus they can be associated files.

I was able to use some of your code and I left the parts out that targeted just the 'mytxt" format and the Boolean pre-Check.

All works perfectly.

FYI, when I upload this updated version tomorrow, It will have a messagebox (see screen below) that gives you credit.


The project is here (doesn't have your contributed code yet though)
https://www.pixelink.media/pixelreader.php


THANK YOU FOR ALL YOUR HELP!