Basically, you need to add two keys to the registry under HKEY_CLASSES_ROOT. Say your extension
in ".ext", then the first key you add is the extension itself:
HKEY_CLASSES_ROOT\
.ext\
and set the "default" string value of this key to an "internal name" for your file type - for example
MyApp.Document:
HKEY_CLASSES_ROOT\
.ext\
Default = "MyApp.Document"
You then create another key with this name:
HKEY_CLASSES_ROOT\
MyApp.Document\
Create a sub-key of this called "shell", a sub-key of *this* called "open" and a further sub-key of "open"
called "command". The default value uder this key is the location and name of your your application folled
by "%1" which represents the filename parameter that Windows will pass to your executable:
HKEY_CLASSES_ROOT\
MyApp.Document\
shell\
open\
command\
Default = "C:\myapp\myapp.exe %1"
You can do this in code with the TRegistry object, or use InstallShield, which can make registry changes for
you. I'd advise doing both, in case the user trashes your registry entry. From: "Rodney E Geraghty"
&tt;gerarod@ibm.net>
The easiest way I've found to do this is to modify the Extensions section of the win.ini file that is located in
the Windows directory. This also works under Win 95 and will update the registry automatically under
Win95. Look at the extensions section of the win.ini to see the format you have to use. Put IniFiles in your
uses clause and then use something like this:
var
INIFile: TIniFile;
begin
try
INIFile := TInifile.Create('WIN.INI');
INIFile.WriteString('Extensions','txt','c:\windows\notepad.exe ^.txt');
finally
INIFile.Free;
end;
end;
This would associate *.txt files with Windows Notepad. If you had an app named MyApp in the
c:\MyApps directory and your extension was *.MAP then you would change it like this:
var
INIFile: TIniFile;
begin
try
INIFile := TInifile.Create('WIN.INI');
INIFile.WriteString('Extensions','map','c:\myapps\myapp.exe ^.map');
finally
INIFile.Free;
end;
end;
This will work in both Win 3.11 and Win 95 and saves you from having to modify the Reqistry under Win
95. Not sure about Win NT (or Win95b) since I don't have a test machine available. Note that this is only
the first part of the solution though since it will open the associated application but it won't load the file you
clicked. To do this you have to read ParamStr(1), which would hold the full path of the file you clicked, and
run the file name through your file opening routine.