How to get the Full Path of a File? - c#

I try to get the Full Path of a File. ie. calc
Input: calc
Expected output: C:\WINDOWS\system32\calc.exe
I could find out how to do it with PowerShell:
(Get-Command calc).Source
Or with CommandLine:
where.exe calc
But unfortunately I can not get it done with C#.

The documentation for Get-Command says:
Get-Command * gets all types of commands, including all of the non-PowerShell files in the Path environment variable ($env:Path), which it lists in the Application command type.
So we will need to get the Path environment variable and iterate over the directories it lists, looking for files with extensions that indicate the file is a program, for example "*.com" and "*.exe".
The problem with the Path environment variable is that it can become polluted with non-existent directories, so we will have to check for those.
The case of the filename and extension don't matter, so case-insensitive comparisons need to be made.
static void ShowPath(string progName)
{
var extensions = new List<string> { ".com", ".exe" };
string envPath = Environment.GetEnvironmentVariable("Path");
var dirs = envPath.Split(new char[] { ';' }, StringSplitOptions.RemoveEmptyEntries);
foreach (string d in dirs.Where(f => Directory.Exists(f)))
{
foreach (var f in (Directory.EnumerateFiles(d).
Where(thisFile => extensions.Any(h => Path.GetExtension(thisFile).Equals(h, StringComparison.InvariantCultureIgnoreCase)))))
{
if (Path.GetFileNameWithoutExtension(f).Equals(progName, StringComparison.InvariantCultureIgnoreCase))
{
Console.WriteLine(f);
return;
}
}
}
Console.WriteLine("Not found.");
}
static void Main(string[] args)
{
ShowPath("calc");
Console.ReadLine();
}
Output:
C:\WINDOWS\system32\calc.exe
There is always the possibility that the current user does not have permission to list the files from somewhere in the path, so checks should be added for that. Also, you might want to use StringComparison.CurrentCultureIgnoreCase for the comparison.

You can get the Pathenvironment variable, split it with ; as delimiter and loop over that result. Then, check if the file path + #"\" + name + ".exe" exists.
var findMe = "calc";
var pathes = Environment.GetEnvironmentVariable("Path").Split(';');
foreach (var path in pathes)
{
var testMe = $#"{path}\{findMe}.exe";
if (File.Exists(testMe))
{
Console.WriteLine(testMe);
}
}
This outputs :
C:\WINDOWS\system32\calc.exe

I do not know about any way of doing that exact thing from C# either. However the paths are usually well known and can be retreived via the SpecialFolders Enumeration:
using System;
using System.Diagnostics;
using System.IO;
namespace RunAsAdmin
{
class Program
{
static void Main(string[] args)
{
/*Note: Running a batch file (.bat) or similar script file as admin
Requires starting the interpreter as admin and handing it the file as Parameter
See documentation of Interpreting Programm for details */
//Just getting the Absolute Path for Notepad
string windir = Environment.GetFolderPath(Environment.SpecialFolder.Windows);
string FullPath = Path.Combine(windir, #"system32\notepad.exe");
//The real work part
//This is the programm to run
ProcessStartInfo startInfo = new ProcessStartInfo(FullPath);
//This tells it should run Elevated
startInfo.Verb = "runas";
//And that gives the order
//From here on it should be 100% identical to the Run Dialog (Windows+R), except for the part with the Elevation
System.Diagnostics.Process.Start(startInfo);
}
}
}
I did not just use System (37) back then, as I wrote it when x32/x86 Systems were still a thing. You would need to check how it resolves nowadays.
Note that most of those paths are duplicated in the PATH System Variable, so you could look it up: https://www.architectryan.com/2018/03/17/add-to-the-path-on-windows-10/
Path Variables in turn go back to the old DOS days. Basically if you gave the Commandline a command/filename it would try the build-in commands, then Executables in the current working Directory (.bat, .com, .exe), and then go look over the path directories to again look for executeables. And only if all that failed, would it complain.

I finally tried to combine all three answers and came up with this:
I post it here in case someone has the same problem.
public static string[] GetPathOf(string cmd)
{
var list = new List<string>();
list.AddRange(Environment.GetEnvironmentVariable("path", EnvironmentVariableTarget.Machine).Split(';'));
list.AddRange(Environment.GetEnvironmentVariable("path", EnvironmentVariableTarget.Process).Split(';'));
list.AddRange(Environment.GetEnvironmentVariable("path", EnvironmentVariableTarget.User).Split(';'));
list = list.Distinct().Where(e=>Directory.Exists(e)).SelectMany(e=> new DirectoryInfo(e).GetFiles()).Where(e=>Regex.IsMatch(e.Name,"(?i)^"+cmd+"\\.(?:exe|cmd|com)")).Select(e=>e.FullName).ToList();
return list.ToArray();
}

Related

How to build a list of directories from args that may contain drive letters and/or wildcards

I want to pass a list of directories to my C# console application as arguments which may be relative paths based on the current working directory, or contain drive letters and/or wildcards. E.g.:
myApp.exe someDir another\dir dirs\with\wild*cards* ..\..\a\relative\dir C:\an\absolute\dir\with\wild*cards*
So far I've come up with this:
static void Main(string[] args)
{
List<string> directories = new List<string>();
foreach (string arg in args)
{
if (Directory.Exists(arg))
{
// 'arg' by itself is a valid directory, and must not contain any wildcards
// just add it to 'directories'
directories.Add(arg);
}
else
{
// 'arg' must either be a non-existant directory or invalid directory name,
// or else it contains wildcard(s). Find all matching directory names, starting
// at the current directory (assuming 'arg' might be a relative path), and add
// all matching directory names to 'directories'.
string[] dirs = Directory.GetDirectories(Directory.GetCurrentDirectory(), arg, SearchOption.TopDirectoryOnly);
directories.AddRange(dirs);
}
}
Console.WriteLine("Full list of directories specified by the command line args:");
foreach (string dir in directories)
{
Console.WriteLine(" " + dir);
}
// Now go do what I want to do for each of these directories...
}
This works great for someDir, another\dir, and dirs\with\wild*cards*, but won't work for ..\..\a\relative\dir or C:\an\abolute\dir\with\wild*cards*. For the relative dir, Directory.GetDirectories() throws a System.ArgumentException saying "Search pattern cannot contain '..' to move up directories and can be contained only internally in file/directory names, as in 'a..b'." For the drive-letter-based directory, it throws a System.ArgumentException saying "Second path fragment must not be a drive or UNC name."
How can I handle the ".." and drive letters? This has to be a solved problem, but I can't find examples of such for C#.
"Bonus question": My above code also doesn't handle a\path\with\wild*cards*\in\anything\other\than\the\top\directory. Any easy way to handle that too?
Couple of observations:
1) To check if path absolute or relative - you can use Path.IsRooted()
2) To resolve path with ".." to absolute path (be it relative or absolute) you can use:
path = new Uri(Path.Combine(Directory.GetCurrentDirectory(), path)).AbsolutePath;
Routing it though Uri expands those dots. Path.GetFullPath will fail in case of wildcards, but Uri will not.
3) To check if path contains wildcards you can just do path.Contains("*") || path.Contains("?") since both of those characters are not valid path chars, so cannot be present in a context other than being wildcards.
4) To resolve wildcard in absolute path (and match your "bonus" requirement) you need to find out first directory which does not contain wildcard. So you basically need to split path into to parts - before first wildcard and after first wildcard. For example:
C:\an\abolute\dir\with\wild*cards*
Path before wildcard is C:\an\abolute\dir\with, after (and including) wildcard: wild*cards*.
C:\an\abolu*e\dir\with\wild*cards*
Path before first wildcard: C:\an, after: abolu*e\dir\with\wild*cards*. There are different ways to do that of course, easiest I think is regex:
#"[\\/](?=[^\\/]*[\*?])"
It basically matches directory separator, but only if it is followed by 0 or more charactres which are NOT directory separators, then followed by wildcard symbol.
Combining this all together we have:
static IEnumerable<string> ResolveDirectories(string path) {
if (path.Contains("*") || path.Contains("?")) {
// we have a wildcard,
// resolve it to absolute path if necessary
if (!Path.IsPathRooted(path))
path = Path.Combine(Directory.GetCurrentDirectory(), path);
// resolve .. stuff if any
path = new Uri(Path.Combine(Directory.GetCurrentDirectory(), path)).AbsolutePath;
// split with regex above, only on first match (2 parts)
var parts = new Regex(#"[\\/](?=[^\\/]*[\*?])").Split(path, 2);
var searchRoot = parts[0];
var searchPatterns = parts[1].Split(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar);
foreach (var dir in ResolveWildcards(searchRoot, searchPatterns))
yield return dir;
}
else {
// this should work with "../.." type of paths too, will resolve relative to current directory
// so no processing is necessary
if (Directory.Exists(path)) {
yield return path;
}
else {
// invalid directory?
}
}
}
static IEnumerable<string> ResolveWildcards(string searchRoot, string [] searchPatterns) {
// if we have path C:\an\abolu*e\dir\with\wild*cards*
// search root is C:\an
// and patterns are: [abolu*e, dir, with, wild*cards*]
if (Directory.Exists(searchRoot)) {
// use next pattern to search in a search root
var next = searchPatterns[0];
// leave the rest for recursion
var rest = searchPatterns.Skip(1).ToArray();
foreach (var dir in Directory.EnumerateDirectories(searchRoot, next, SearchOption.AllDirectories)) {
// if nothing left (last pattern) - return it
if (rest.Length == 0)
yield return dir;
else {
// otherwise search with rest patterns in freshly found directory
foreach (var sub in ResolveWildcards(dir, rest))
yield return sub;
}
}
}
}
This is not properly tested, so take care.
'Evk' posted his/her answer a few minutes before I was about to post this, so I have not evaluated Evk's answer.
After finding this question+answer which might have worked fine but I didn't test it, I stumbled across Michael Ganss's Glob.cs NuGet package, and the results are very nice:
// Requires Glob.cs, (c) 2013 Michael Ganss, downloaded via the NuGet package manager:
// https://www.nuget.org/packages/Glob.cs
// (In Visual Studio, go to Tools->NuGet Package Manager->Package Manager Console.)
// PM> Install-Package Glob.cs -Version 1.3.0
using Glob;
namespace StackOverflow_cs
{
class Program
{
static void Main(string[] args)
{
List<string> directories = new List<string>();
foreach (string arg in args)
{
var dirs = Glob.Glob.Expand(arg, true, true);
foreach (var dir in dirs)
{
directories.Add(dir.FullName);
}
}
Console.WriteLine("Full list of directories specified by the command line args:");
foreach (string dir in directories)
{
Console.WriteLine(" " + dir);
}
// Now go do what I want to do for each of these directories......
}
}
}
But I don't know why I have to say "Glob.Glob.Expand()" instead of simply "Glob.Expand()". Anyway, it works beautifully.

Check if path is in Program Files [duplicate]

This question already has answers here:
See if file path is inside a directory
(2 answers)
Closed 9 years ago.
How can I check in C# if the specific path is to directory in "Program Files" ?
C:\Program Files\someDir... -> is in Program Files
D:\Apps\someDir... -> isn't in Program Files
Thanks!
You can check a path in ProgramFiles(x86) by using the code below:
string path = "yourpath";
var programfileX86 = Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86);
if (path.IndexOf(programfileX86, StringComparison.OrdinalIgnoreCase) >= 0)
{
//Found path
}
There're some interseting and subtle issues with the problem:
You should compare paths case insenstive, e.g. "C:\PRogRAM FILES (x86)\Sample" is OK
Separators could be either / or \ so "C:/PRogRAM FILES (x86)/Sample" is OK as well
You should break on separatos only, e.g. "C:\Program Files (x86)MyData\Sample" is not OK
The Code:
public static Boolean PathIncludes(String path, String pathToInclude) {
if (String.IsNullOrEmpty(pathToInclude))
return false;
else if (String.IsNullOrEmpty(path))
return false;
String[] parts = Path.GetFullPath(path).Split(Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar, Path.VolumeSeparatorChar);
String[] partsToInclude = Path.GetFullPath(pathToInclude).Split(Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar, Path.VolumeSeparatorChar);
if (parts.Length < partsToInclude.Length)
return false;
for (int i = 0; i < partsToInclude.Length; ++i)
if (!String.Equals(parts[i], partsToInclude[i], StringComparison.OrdinalIgnoreCase))
return false;
return true;
}
public static Boolean InProgramFiles(String path) {
return PathIncludes(path, Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86)));
}
// Tests:
// Supposing that ProgramFilesX86 is "C:\Program Files (x86)"
InProgramFiles(#"C:\PRogRAM FILES (x86)\Sample"); // <- true
InProgramFiles(#"C:/PRogRAM FILES (x86)/Sample"); // <- true
InProgramFiles(#"D:/PRogRAM FILES (x86)/Sample"); // <- false
InProgramFiles(#"C:/PRogRAM FILES (x86)A/Sample"); // <- false
First you need to get the program files path. You can do that with System.Environment:
var programFilesPath = System.Environment.GetFolderPath(System.Environment.SpecialFolder.ProgramFiles);
If you want the 32 bit program files path you would just change the special folder you are looking for (System.Environment.SpecialFolder.ProgramFilesX86). Then I would do a contains:
var isInProgramFiles = myPath.ToLower().Contains(programFilesPath.ToLower());
That should get you 90% of the way there at least! Best of luck!
EDIT / Sanitize Note
As a side note - there are situations where you can have a valid input and this still wouldn't match. For example - using "/" instead of "\". If you want to make sure you handle these boundary cases correctly, you can create a "DirectoryInfo" object from your input string, validate that it is actually a folder and also standardize the formatting for it. That code looks something like:
if (!System.IO.Directory.Exists(inputPath)) return false;
var checkPath = (new System.IO.DirectoryInfo(inputPath)).FullName;
In this example "inputPath" is the same as "myPath" was above. That should do a moderately good job of sanitizing the input. Best of luck!
If you have a path variable:
string path = "/* whatever path */";
You can check if it is in a folder subfolder this way:
path.IndexOf('\\' + subfolder + '\\') != -1
Note that in more complex cases .. may revert you out of a subdirectory, meaning that you are not in folder f2 if you have something like this:
"\\base_on_drive\\subfolder\\f1\\f2\\..\\a_file.txt"
The .. will bump you back into it's parent folder f1.
if (path.Contains(Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles)) || (path.Contains(Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86)))
{
}
Assuming your program might be running inside of ProgramFiles, you will probably want to get the fullpath of any path you're checking (in case you get a relative path). In addition, C# has a handy SpecialFolder enumeration that you can use to get the ProgramFiles directory.
The following code will take in a path, convert it to a fullpath, and check if the ProgramFiles directory can be found inside of it. You may want to add some error handling (such as checking for null paths).
static string programfileX86 = Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86);
public bool IsInsideProgramFiles(string path)
{
// Get the fullpath in case 'path' is a relative path
string fullPath = System.IO.Path.GetFullPath(path);
return (fullPath.IndexOf(programfileX86, StringComparison.OrdinalIgnoreCase) >= 0);
}
Note: Depending on the systems your code is running in, you may want to check for both SpecialFolder.ProgramFiles and SpecialFolder.ProgramFilesx86.
Credit goes to Toan Nguyen's for the code to get the ProgramFiles directory:

How can I quickly identify the path and the search pattern in C:\Users\Admin\Samples\*.pdf?

I would like to create a simple copy console application (I know copy already exists in DOS). Exactly like the DOS copy command I would like to be able to execute my copy application with two simple arguments:
copy C:\Users\Admin\Samples\*.pdf C:\
Input path and search pattern
Ouput path
In my code I use this
static void Main(string[] args)
{
string input;
string output;
var options = new Options();
ICommandLineParser parser = new CommandLineParser();
if (parser.ParseArguments(args, options))
{
input = options.Argument[0];
output = options.Argument[1];
// Get file list
String directory = Path.GetDirectoryName(input);
String[] files = Directory.GetFiles(directory, /* ??? */);
// To be continued...
}
else
{
System.Console.WriteLine("Erreur");
System.Console.ReadKey();
}
}
How can I easely retrieve my search pattern? Is beter way to do this?
Try this:
string extension = System.IO.Path.GetExtension(input);
string inputDirectory = System.IO.Path.GetDirectoryName(input);
I think this is what you wanted.
To get the path, or the file, of the input parameter, you can use the following:
Path.GetFileName(input);

How do I deal with Paths when writing a PowerShell Cmdlet?

What is the proper way to receive a file as a parameter when writing a C# cmdlet? So far I just have a property LiteralPath (aligning with their parameter naming convention) that is a string. This is a problem because you just get whatever is typed into the console; which could be the full path or could be a relative path.
Using Path.GetFullPath(string) doesn't work. It thinks I'm currently at ~, I'm not. Same problem occurs if I change the property from a string to a FileInfo.
EDIT: For anyone interested, this workaround is working for me:
SessionState ss = new SessionState();
Directory.SetCurrentDirectory(ss.Path.CurrentFileSystemLocation.Path);
LiteralPath = Path.GetFullPath(LiteralPath);
LiteralPath is the string parameter. I'm still interested in learning what is the recommended way to handle file paths that are passed as parameters.
EDIT2: This is better, so that you don't mess with the users current directory, you should set it back.
string current = Directory.GetCurrentDirectory();
Directory.SetCurrentDirectory(ss.Path.CurrentFileSystemLocation.Path);
LiteralPath = Path.GetFullPath(LiteralPath);
Directory.SetCurrentDirectory(current);
This is a surprisingly complex area, but I have a ton of experience here. In short, there are some cmdlets that accept win32 paths straight from the System.IO APIs, and these typically use a -FilePath parameter. If you want to write a well behaved "powershelly" cmdlet, you need -Path and -LiteralPath, to accept pipeline input and work with relative and absolute provider paths. Here's an excerpt from a blog post I wrote a while ago:
Paths in PowerShell are tough to understand [at first.] PowerShell Paths - or PSPaths, not to be confused with Win32 paths - in their absolute forms, they come in two distinct flavours:
Provider-qualified: FileSystem::c:\temp\foo.txt
PSDrive-qualified: c:\temp\foo.txt
It's very easy to get confused over provider-internal (The ProviderPath property of a resolved System.Management.Automation.PathInfo – the portion to the right of :: of the provider-qualified path above) and drive-qualified paths since they look the same if you look at the default FileSystem provider drives. That is to say, the PSDrive has the same name (C) as the native backing store, the windows filesystem (C). So, to make it easier for yourself to understand the differences, create yourself a new PSDrive:
ps c:\> new-psdrive temp filesystem c:\temp\
ps c:\> cd temp:
ps temp:\>
Now, let's look at this again:
Provider-qualified: FileSystem::c:\temp\foo.txt
Drive-qualified: temp:\foo.txt
A bit easier this time to see what’s different this time. The bold text to the right of the provider name is the ProviderPath.
So, your goals for writing a generalized provider-friendly Cmdlet (or advanced function) that accepts paths are:
Define a LiteralPath path parameter aliased to PSPath
Define a Path parameter (which will resolve wildcards / glob)
Always assume you are receiving PSPaths, NOT native provider-paths (e.g. Win32 paths)
Point number three is especially important. Also, obviously LiteralPath and Path should belong in mutually exclusive parameter sets.
Relative Paths
A good question is: how do we deal with relative paths being passed to a Cmdlet. As you should assume all paths being given to you are PSPaths, let’s look at what the Cmdlet below does:
ps temp:\> write-zip -literalpath foo.txt
The command should assume foo.txt is in the current drive, so this should be resolved immediately in the ProcessRecord or EndProcessing block like (using the scripting API here to demo):
$provider = $null;
$drive = $null
$pathHelper = $ExecutionContext.SessionState.Path
$providerPath = $pathHelper.GetUnresolvedProviderPathFromPSPath(
"foo.txt", [ref]$provider, [ref]$drive)
Now you everything you need to recreate the two absolute forms of PSPaths, and you also have the native absolute ProviderPath. To create a provider-qualified PSPath for foo.txt, use $provider.Name + “::” + $providerPath. If $drive is not $null (your current location might be provider-qualified in which case $drive will be $null) then you should use $drive.name + ":\" + $drive.CurrentLocation + "\" + "foo.txt" to get a drive-qualified PSPath.
Quickstart C# Skeleton
Here's a skeleton of a C# provider-aware cmdlet to get you going. It has built in checks to ensure it has been handed a FileSystem provider path. I am in the process of packaging this up for NuGet to help others get writing well-behaved provider-aware Cmdlets:
using System;
using System.Collections.Generic;
using System.IO;
using System.Management.Automation;
using Microsoft.PowerShell.Commands;
namespace PSQuickStart
{
[Cmdlet(VerbsCommon.Get, Noun,
DefaultParameterSetName = ParamSetPath,
SupportsShouldProcess = true)
]
public class GetFileMetadataCommand : PSCmdlet
{
private const string Noun = "FileMetadata";
private const string ParamSetLiteral = "Literal";
private const string ParamSetPath = "Path";
private string[] _paths;
private bool _shouldExpandWildcards;
[Parameter(
Mandatory = true,
ValueFromPipeline = false,
ValueFromPipelineByPropertyName = true,
ParameterSetName = ParamSetLiteral)
]
[Alias("PSPath")]
[ValidateNotNullOrEmpty]
public string[] LiteralPath
{
get { return _paths; }
set { _paths = value; }
}
[Parameter(
Position = 0,
Mandatory = true,
ValueFromPipeline = true,
ValueFromPipelineByPropertyName = true,
ParameterSetName = ParamSetPath)
]
[ValidateNotNullOrEmpty]
public string[] Path
{
get { return _paths; }
set
{
_shouldExpandWildcards = true;
_paths = value;
}
}
protected override void ProcessRecord()
{
foreach (string path in _paths)
{
// This will hold information about the provider containing
// the items that this path string might resolve to.
ProviderInfo provider;
// This will be used by the method that processes literal paths
PSDriveInfo drive;
// this contains the paths to process for this iteration of the
// loop to resolve and optionally expand wildcards.
List<string> filePaths = new List<string>();
if (_shouldExpandWildcards)
{
// Turn *.txt into foo.txt,foo2.txt etc.
// if path is just "foo.txt," it will return unchanged.
filePaths.AddRange(this.GetResolvedProviderPathFromPSPath(path, out provider));
}
else
{
// no wildcards, so don't try to expand any * or ? symbols.
filePaths.Add(this.SessionState.Path.GetUnresolvedProviderPathFromPSPath(
path, out provider, out drive));
}
// ensure that this path (or set of paths after wildcard expansion)
// is on the filesystem. A wildcard can never expand to span multiple
// providers.
if (IsFileSystemPath(provider, path) == false)
{
// no, so skip to next path in _paths.
continue;
}
// at this point, we have a list of paths on the filesystem.
foreach (string filePath in filePaths)
{
PSObject custom;
// If -whatif was supplied, do not perform the actions
// inside this "if" statement; only show the message.
//
// This block also supports the -confirm switch, where
// you will be asked if you want to perform the action
// "get metadata" on target: foo.txt
if (ShouldProcess(filePath, "Get Metadata"))
{
if (Directory.Exists(filePath))
{
custom = GetDirectoryCustomObject(new DirectoryInfo(filePath));
}
else
{
custom = GetFileCustomObject(new FileInfo(filePath));
}
WriteObject(custom);
}
}
}
}
private PSObject GetFileCustomObject(FileInfo file)
{
// this message will be shown if the -verbose switch is given
WriteVerbose("GetFileCustomObject " + file);
// create a custom object with a few properties
PSObject custom = new PSObject();
custom.Properties.Add(new PSNoteProperty("Size", file.Length));
custom.Properties.Add(new PSNoteProperty("Name", file.Name));
custom.Properties.Add(new PSNoteProperty("Extension", file.Extension));
return custom;
}
private PSObject GetDirectoryCustomObject(DirectoryInfo dir)
{
// this message will be shown if the -verbose switch is given
WriteVerbose("GetDirectoryCustomObject " + dir);
// create a custom object with a few properties
PSObject custom = new PSObject();
int files = dir.GetFiles().Length;
int subdirs = dir.GetDirectories().Length;
custom.Properties.Add(new PSNoteProperty("Files", files));
custom.Properties.Add(new PSNoteProperty("Subdirectories", subdirs));
custom.Properties.Add(new PSNoteProperty("Name", dir.Name));
return custom;
}
private bool IsFileSystemPath(ProviderInfo provider, string path)
{
bool isFileSystem = true;
// check that this provider is the filesystem
if (provider.ImplementingType != typeof(FileSystemProvider))
{
// create a .NET exception wrapping our error text
ArgumentException ex = new ArgumentException(path +
" does not resolve to a path on the FileSystem provider.");
// wrap this in a powershell errorrecord
ErrorRecord error = new ErrorRecord(ex, "InvalidProvider",
ErrorCategory.InvalidArgument, path);
// write a non-terminating error to pipeline
this.WriteError(error);
// tell our caller that the item was not on the filesystem
isFileSystem = false;
}
return isFileSystem;
}
}
}
Cmdlet Development Guidelines (Microsoft)
Here is some more generalized advice that should help you out in the long run:
http://msdn.microsoft.com/en-us/library/ms714657%28VS.85%29.aspx

hijack program’s command to run notepad

I have a utility programs’s EXE file, when i run this file there is a winform only and there is button when we click on it, it run windows’s notepad. Now I want to hijack this program’s command to run notepad and instead of running notepad I want to run MS Word. I know C# and VB.NET. What I need to do this ?
You can try to add in folder with this program your own program called notepad.exe that should do only one thing: run word.
If you want to do it programatically in C then you should read this page - maybe it helps: Intercepted: Windows Hacking via DLL Redirection
You can use a trick to replace programs with another by making changes to the registry. This will work even if the program you are running uses absolute paths to run notepad. It overrides any instance of the running program with the chosen one no matter where it resides. And you won't have to patch the file. The key you'd be interested in is:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
Add a key with the name of the program and add a Debugger string with the path to the program you want to replace it with. Of course you need to have permissions to make the necessary modifications. This page explains how you can replace Windows Notepad with another program. You can apply the same process here.
Though you'll probably not want to have this permanent change, so you can write up a program to temporarily add/change the key, run your program then change it back. Here's a complete one I just whipped up to temporarily replace Notepad with Word for a demonstration. Seems to work perfectly fine (though as always, use at your own risk). Just make all the necessary changes to fit your situation.
using System.Diagnostics;
using Microsoft.Win32;
namespace ProgramLauncher
{
class Program
{
// change the following constants as needed
const string PROGRAM_NAME = #"notepad.exe";
const string REPLACEMENT_PATH = #"C:\Program Files (x86)\Microsoft Office\Office12\WINWORD.EXE";
const string RUNNING_PATH = #"C:\Windows\notepad.exe";
// root key
const string KEY = #"SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options";
static void Main(string[] args)
{
using (var rootKey = Registry.LocalMachine.OpenSubKey(KEY, RegistryKeyPermissionCheck.ReadWriteSubTree))
{
var oldPath = default(string);
var needsRestoration = false;
try
{
oldPath = BackupKey(rootKey, PROGRAM_NAME, REPLACEMENT_PATH);
needsRestoration = true;
Process.Start(RUNNING_PATH).WaitForExit();
}
finally
{
if (needsRestoration)
RestoreKey(rootKey, PROGRAM_NAME, oldPath);
}
}
}
static string BackupKey(RegistryKey rootKey, string programName, string newPath)
{
Debug.Assert(rootKey != null);
Debug.Assert(!string.IsNullOrEmpty(programName));
Debug.Assert(!string.IsNullOrEmpty(newPath) && System.IO.File.Exists(newPath));
if (newPath.Contains(" "))
newPath = string.Format("\"{0}\"", newPath);
using (var programKey = rootKey.CreateSubKey(programName, RegistryKeyPermissionCheck.ReadWriteSubTree))
{
var oldDebugger = programKey.GetValue("Debugger") as string;
programKey.SetValue("Debugger", newPath, RegistryValueKind.String);
return oldDebugger;
}
}
static void RestoreKey(RegistryKey rootKey, string programName, string oldPath)
{
Debug.Assert(rootKey != null);
Debug.Assert(!string.IsNullOrEmpty(programName));
if (oldPath != null)
{
using (var programKey = rootKey.OpenSubKey(programName, RegistryKeyPermissionCheck.ReadWriteSubTree))
programKey.SetValue("Debugger", oldPath);
}
else
{
rootKey.DeleteSubKey(programName);
}
}
}
}

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