I would like to access the file from which the following is read off.
File types/associations are stored in the HKEY_CLASSES_ROOT part of the registry.
Which application (which ProgId technically) is the default for a specific file extension is stored inside the undocumented HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts key. The UserChoice is hashed to prevent people from changing the default.
Related
I have an EXE file, and i whant to launch it every windows start for all users.
am adding a registry key on :
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
My EXE works fine, but it can't access to any other file (.txt) even the required file is in the same location.
it seems like an access denied. why?
My Exe is a .NET application (C# console application) reading a text file content.
Solution from #HansPassant :
Always use full path names for files, c:\foo\bar\baz.txt. Just baz.txt will not work, the Environment.CurrentDirectory is not set where you hope it is. Use AppData, if necessary use Path.GetDirectoryName(Assembly.GetEntryAssembly().Location) to know where your EXE was installed.
I need to be able to access the 'Remote Path' that is entered by the user in the 'DNC-T Device Setting' Utility program. Are these paths stored in a ini file or in the registry?
The DNC-T Device Setting Utility is an "easy access" approach to modifying registry keys.
The Program (located in C:\OSP-P\Tools\)
Not only can you see which locations have been added, but following this pattern you could add / modify / or delete keys as well. They are stored in the registry in the following location:
HKEY_LOCAL_MACHINE\SOFTWARE\OKUMA\DNC-T\
I have my application written in Delphi XE that works with PDF files. Applicaiton is Win32. On start I would like to ensure that there is my item in explorer context menu for PDF files. I would like to be able to specify whether it should be added for active user only or for all users (with UAC I will need to restart with Admin privileges but thats ok).
I started with How to associate a Delphi program with a file type, but only for the current user? and How to add item to windows explorer content menu in delphi? . I tested it with manual registry editing via regedit and it worked fine for "new" extensions. But for .pdf it is more complicated as it will be most probably already present in the registry.
On my PC the .pdf key is referencing AcroExch.Document . But adding shell/something subkey to the AcroExch.Document key is not working because it has CurVer subkey referencing to AcroExch.Document.7. However another PC with another verison of Acrobat had this names a little different. It is no problem for me to follow the CurVer reference but is that a correct approach? And what about situation where no PDF reader is installed, how should I name my keys so Acrobat won't overwrite them when installed?
But more pressing matter is in which root should I put my keys? How to associate a Delphi program with a file type, but only for the current user? is mentioning HKLM (Local Machine) and HKCU (Current user). Its seems rather straightforward but I am unable to set values in HKLM from Delphi. Strangely I can create keys:
var reg:TRegistry;
key := '\Software\Classes\'+keyname+'\shell\'+name+'\command';
reg.CreateKey(key);
but I am getting Access Denied when trying to write the actual value:
reg.OpenKey(key,false);
reg.WriteString('',command);
I am getting the same Access Denied exception even on WinXP, no matter if the applicaiton is running as Admin (Win7), I even tried to set permissions (Everyone full control) for the key via regedit (I can edit the value via regedit without problems). I tried creating the registry with different access modes, all with no luck:
reg := TRegistry.Create(KEY_WRITE or KEY_WOW64_64KEY);
reg := TRegistry.Create(KEY_ALL_ACCESS or KEY_WOW64_64KEY);
reg.Access := KEY_ALL_ACCESS;
reg.Access := KEY_WRITE or KEY_WOW64_64KEY;
reg.Access := KEY_ALL_ACCESS or KEY_WOW64_64KEY;
With HKCU everything works fine.
So I tried writing into HKEY_CLASSES_ROOT and it works and actually puts the keys exactly where I want (into HKLM) if running as Admin. But according to http://msdn.microsoft.com/en-us/library/windows/desktop/ms724475.aspx
The HKEY_CLASSES_ROOT (HKCR) key contains file name extension associations and COM class registration information such as ProgIDs, CLSIDs, and IIDs. It is primarily intended for compatibility with the registry in 16-bit Windows.
I do not like the note about the primary purpose being compatibile with 16-bit Windows. And the actual conditions where the changes will be written is more complicated than I would like.
So basically I have these questions:
What is the advantage of using AcroExch.Document and CurVer instead of pointing directly to AcroExch.Document.7? And what are the "best manners" when adding my keys into this structure? What about the case when the .pdf is not yet associated with anything?
Where should I put my keys and why I am not able to write into HKLM?
Edit:
The problem with Access Denied when writing to HKLM was caused by my error. I did use in previous code openKeyReadOnly and I did not notice that it will swtich the Access property to readonly for all subsequent calls.
To answer your other question, if Adobe is not installed yet then obviously the PDF keys will likely not exist in the Registry yet so you would have to create your own .pdf and ProgID keys so that you can attach your Shell command on it. If Adobe is installed afterwards, it is likely going to wipe out your keys and replace them with its own, so you would have to recreate your Shell command within Adobe's key structure. Your app can query the Registry to check for that condition periodically, such as at startup.
You have asked two separate questions. Since I know the answer to one and not the other, I'm going to answer just one. For future reference, I do recommend that you ask a single question at a time.
Where should I put my keys?
You are correct in discerning that you should not use HKCR. The documentation for HKCR says:
Class registration and file name extension information is stored under
both the HKEY_LOCAL_MACHINE and HKEY_CURRENT_USER keys. The
HKEY_LOCAL_MACHINE\Software\Classes key contains default settings that
can apply to all users on the local computer. The
HKEY_CURRENT_USER\Software\Classes key contains settings that apply
only to the interactive user. The HKEY_CLASSES_ROOT key provides a
view of the registry that merges the information from these two
sources. HKEY_CLASSES_ROOT also provides this merged view for
applications designed for previous versions of Windows.
....
If you write keys to a key under HKEY_CLASSES_ROOT, the system stores
the information under HKEY_LOCAL_MACHINE\Software\Classes. If you
write values to a key under HKEY_CLASSES_ROOT, and the key already
exists under HKEY_CURRENT_USER\Software\Classes, the system will store
the information there instead of under
HKEY_LOCAL_MACHINE\Software\Classes.
So, it is reasonable to use HKCR for reading, but for writing you typically need to exert control over whether to write to HKLM or HKCU. And that means that you cannot write to HKCR.
So, write to HKLM\Software\Classes for machine-wide settings, and HKCU\Software\Classes for user-specific settings.
Note that in Windows 7 and later neither of these keys is redirected and so you do not need to worry about using KEY_WOW64_64KEY. However, in Vista and XP64, and the equivalent server editions, these keys are redirected and reflected. Which means that it might be prudent to use KEY_WOW64_64KEY.
I know that many questions are asked about how customizing the shell context menu, but what I've tried yet doesn't work so I'm adding a new question.
I'd like to add an entry "Open with Log Viewer" in the context menu when right-clicking on files with ".log" extension, to not change the default application associated with .log files (notepad) but allow the user to choose a custom application to open them.
To do this, I opened the registry key HKEY_CLASSES_ROOT\.log, and added some keys shell\OpenWithLogViewer\command with the correct values, but the entry is not displayed when I right-click on a file with .log extension.
Would you know how to fix this?
The key HKEY_CLASSES_ROOT\.log has for default value txtfile, and contains a subkey called PersistentHandler. Can this subkey be the origin of the problem?
Add another registry key (e.g. HKEY_CLASSES_ROOT\logfile), create the shell structure below that key and change the default value of the .log key to logfile. One way to do this is by saving the following lines to a .reg file and merging that file into the registry.
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\.log]
#="logfile"
[HKEY_CLASSES_ROOT\logfile]
[HKEY_CLASSES_ROOT\logfile\shell]
#="OpenWithLogViewer"
; make OpenWithLogViewer the default action
[HKEY_CLASSES_ROOT\logfile\shell\OpenWithLogViewer]
#="Open with &Log Viewer"
; set label and access key
[HKEY_CLASSES_ROOT\logfile\shell\OpenWithLogViewer\command]
#="\"C:\\path\\to\\logviewer.exe\" %1"
This separates the type (logfile) from the extension (.log). That way you can define the possible actions for a type in one place and associate arbitrary extensions with that type.
Note that you can also define this on a per-user basis by using HKEY_CURRENT_USER\Software\Classes instead of HKEY_CLASSES_ROOT. User entries take precedence over system entries. This is useful when you want to change file associations or add custom actions for your own user, but don't have admin privileges on the system.
If you want to add a entry for a file extension you don't "own" and you never want to be the default action then you can use the SystemFileAssociations key:
[HKEY_CLASSES_ROOT\SystemFileAssociations\.log\shell\mycommand]
#="My Command"
[HKEY_CLASSES_ROOT\SystemFileAssociations\.log\shell\mycommand\command]
#="\"c:\\path\\myapp.exe\" \"%1\""
To deal proactively with the consequences of a change to default programs, you can use HKEY_CLASSES_ROOT\SystemFileAssociations to register verbs and other association information. Due to their location after the ProgID in the association array, these registrations are lower priority. These SystemFileAssociationsregistrations are stable even when users change the default programs, and provide a location to register secondary verbs that will always be available for a particular file type.
This key is available on Windows XP and higher...
There's an executable file generated from my program in MFC and I want to use it as the default program to open the .jpg files. That is to say, each time I double click a .jpg file, my program will run.
I tried to add some registry entries linking .jpg files with my program, such as HKEY_CLASSES_ROOT\.jpg\shell\open\command (set its value to "myProgram.exe" "%1"), and HKEY_CLASSES_ROOT\myProgram.
The method works just fine except when some other applications register themselves to open the .jpg files. For example, I have installed acdSee on my computer, so each time I doule click a .jpg file, it always start acdSee instead of my own program. But when I register a completely new type of file with my program, it can be open in the program. I don't know how to set my program as the default opening program of an already registered file programmatically. Can anyone help me solve this problem? Thank you very much!
The more typical/standard way for doing this is to set the default value of the ".jpg" key to a name that identifies the file type more clearly, and then setup the various associated actions there. So for jpgs, you might do this:
HKCR\.jpg
#default = MyApp.JpegImage
HKCR\MyApp.JpegImage\shell\open\command
#default = "myApp.exe "%1""
If some other program decides to register the type, they will replace the default value for HKCR.jpg with some other value, like OtherProgram.Jpg. At that point, you could re-register it to your app by setting the value back to MyApp.JpegImage.
Disclaimer: When making this sort of change, please also try to respect the user's preferences. For instance, when installing your application, give the user the option to set this file association or not set it. You can also provide a command from inside your installed application to reset the associations, if the user should wish to do so.
If you instead wanted to add some additional commands to an existing registered type, you would read the default value of the .jpg key to find the name of the file type. Then you could open that key and add an action to the existing set of actions. For instance, you could add the following:
HKCR\ExistingApp.JpegImage\shell\myopen\
#default = "Open with MyApp"
HKCR\ExistingApp.JpegImage\shell\myopen\command\
#default = "myApp.exe "%1""
Note that by writing a key to HKCR, you're actually writing to HKLM\Software\Classes. This will require administrative privileges. However, you can make per-user changes within a user context by writing your keys to HKCU\Classes\Root instead.
Also, user preferences in HKCU will override the system defaults in HKLM, which sounds like what your problem might be.
This is when a program has not registered an extension as a "Default" (Is the program listed in Set Programs and Defaults in the Control Panel?)
Time to start reading documentation!