Mega Code Archive
Determining the associated application
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Title: Determining the associated application
Question: How can I get the application associated with a document?
Answer:
Where is that information?
--------------------------
The applications associated with the file extensions are stored in
the Windows Registry. To get this information first we should
retrieve the "class" that a file extensions belongs to. This
information can be found at:
HKEY_CLASSES_ROOT\.ext\(default)
where ".ext" is the file extension you want (like ".txt", ".bmp",
etc.). Then we get the command line used to open that kind of files.
To do that, we retrieve the data under
HKEY_CLASSES_ROOT\class\Shell\Open\Command\(default)
where "class" is the file class an extension belongs to. That string
usually has the form
"D:\PATH\APPNAME.EXT" "%1" -OPTIONS
where %1 is a placeholder for the document file to open with the
application, so we should find its position within the string and
replace it with the filename we want to open.
Example
-------
The following function returns the command line of the associated
application to open a documente file:
function GetAssociation(const DocFileName: string): string;
var
FileClass: string;
Reg: TRegistry;
begin
Result := '';
Reg := TRegistry.Create(KEY_EXECUTE);
Reg.RootKey := HKEY_CLASSES_ROOT;
FileClass := '';
if Reg.OpenKeyReadOnly(ExtractFileExt(DocFileName)) then
begin
FileClass := Reg.ReadString('');
Reg.CloseKey;
end;
if FileClass '' then begin
if Reg.OpenKeyReadOnly(FileClass + '\Shell\Open\Command') then
begin
Result := Reg.ReadString('');
Reg.CloseKey;
end;
end;
Reg.Free;
end;
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