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Run an External Program or Batch File From a C# Xamarin Program

I want to have my C# (Xamarin) program run an EXE or batch (BAT) file. The user will be running my program, and will click on one of several buttons, some of which open Web pages and others of which run external programs. These files will be on the same computer as the one running the main program and don't need greater permissions. The overall program will be in Windows, UWP.
I already have code to pull info from the database saying "the button the user clicked references a program and it's (eg) C:\Tools\MyTool.exe". (Real path more like (C:\Users\Me\source\repos\ProductNameV2\ProductName\ProductName.UWP\Assets\EXE\whatever.exe".) I used a "demo.bat" file containing nothing but echo and pause statements, or references to a built-in Windows program like Notepad or Calc that an ordinary command prompt can recognize without an explicit path (ie. that's part of the recognized system Path). Yes, the real path to the dummy file does exist; I checked. I've also explicitly added files demo.bat and dummy.txt to my C# project.
Here's roughly what I've tried so far to actually run a batch file, or an EXE, or just to try opening a text file. Nothing works.
1)
bool check = await Launcher.CanOpenAsync(#"file:///C:\Tools\demo.bat"); // Returns false.
bool check = await Launcher.CanOpenAsync(#"file:///C:\Tools\dummy.txt"); // Returns true.
await Launcher.OpenAsync(#"file:///C:\Tools\demo.bat") // Seems to do nothing; silently fails.
await Launcher.OpenAsync(#"file:///C:\Tools\dummy.txt") // Same.
2)
Process batchProcess = new Process();
batchProcess.StartInfo.FileName = #"file:///C:\Tools\demo.bat"; // Same result with notepad.exe
batchProcess.StartInfo.WindowStyle = ProcessWindowStyle.Normal;
batchProcess.Start();
batchProcess.WaitForExit();
// Result: "Access is denied" error during Start().
3)
var otherProcessInfo = new ProcessStartInfo(#"file:///C:\Tools\demo.bat")
var otherProcess = Process.Start(otherProcessInfo);
otherProcess.WaitForExit();
otherProcess.Close();
// Result: "The system cannot find the file specified" despite it being the same path as in previous examples.
// Also tried literally using the path C:\Tools\demo.bat, without adding that to the C# project.
// One thing that slightly works is to use:
var otherProcessInfo = new ProcessStartInfo("cmd.exe", "/c echo Hello world!");
// This version opens a window and instantly closes it again. With "/c pause" instead, it opens, saying "press any key to continue".
// Chaining multiple commands with newline or semicolon characters doesn't work as a form of batch file.
So: the only tiny success I've had here is to run cmd.exe, to run a one-line command. I suppose that depending on what the batch file must do, there's some possibility of receiving a string, breaking it into lines, then running cmd.exe using method 3 to call them one at a time. Which is ugly at best.
Is there some better way to do this -- to run a batch file or an EXE from within my program?
EDIT: Yes, I did in fact look at documentation before asking. Why did I use URIs? Because of multiple errors telling me that the simple path strings ("C:\this\that") I was using were in an "Invalid URI format". Using Process.Start("notepad.exe") silently fails, doing nothing. Using a method involving System.Diagnostics.Process (found at How to run external program via a C# program? and yes I saw that before) fails with an error of "Access denied" when using my batch file reference, or silently failing (no window opens) using plain old notepad.exe. I avoided setting Process options that say hide the window.
So to rephrase: Is there a way to make my program run some EXE somewhere on the computer, or to run a batch file that has more than one command in it? What is that way?

Using the data you collected, I was able to run a batch file by doing the following:
var strPathToExeOrBat = System.IO.Path.Combine("C:\\Tools", "demo.bat");
var otherProcessInfo = new ProcessStartInfo("cmd.exe", $"/c call \"{strPathToExeOrBat\"");
var otherProcess = Process.Start(otherProcessInfo);
otherProcess.WaitForExit();
otherProcess.Close();
I also think it would be helpful to review the capabilities of the cmd.exe application.
I found this post to be helpful:
https://stackoverflow.com/questions/515309/what-does-cmd-c-mean#:~:text=%2FC%20Carries%20out%20the%20command%20specified%20by%20the%20string%20and,switches%20by%20typing%20cmd%20%2F%3F%20.
In particular the /k option will leave the window open, if you don't want it to close after running a script.
Thank you very much for your question! It really helped me find the answer to this! (at least for my situation of a .NET MAUI windows app, but MAUI is built off of Xamarin.Forms, so you shouldn't have a problem doing the same thing)
EDIT: Updated to use file path from question and string interpolation with System.IO.Path.Combine for slightly greater cross platform capability

PDF Printing happens in random order

I am using Foxit Reader (a PDF Reader) and passing command line arguments to print a pdf pro-grammatically. I understand that we cannot specify the number of copies through command line as from this discussion.
I am developing a win-forms desktop application and for printing multiple copies of PDF document I am using the below code
string foxitReaderInstalledPath = GetFoxitReaderInstalledPath();
while (noOfCopies > 0)
{
Process process = new System.Diagnostics.Process();
process.EnableRaisingEvents = false;
process.StartInfo.CreateNoWindow = true;
process.StartInfo.FileName = foxitReaderInstalledPath;
string arguments = String.Format(#"-t ""{0}"" ""{1}""", this.Path, printerName);
process.StartInfo.Arguments = arguments;
process.Start();
process.WaitForExit();
noOfCopies = noOfCopies - 1;
}
Issue happens when multiple users are giving muliple copies of print to the same printer. The issue is the printed documents gets mixed up in the order in which they get printed. Anyone please let me know how I can avoid this issue?
Many thanks.

You can't avoid this client-side...
IF you really want to avoid it the "client" app which is used by the users has to just send the file to some "centralized server process" with all relevant params... this "centralized process" can then "serialize" the printing so it occurs in correct order...
BUT if the printer you are printing to is accessible from the users systems then it could still happen that a user sends something to the printer (like an image or word document...) which will be printed and disturbing the order a bit...
I think it would make much more sense if you described what your goal is... perhaps there is some better way to solve all this... are you implementing a print server ?
EDIT - as per comment:
Put the location for the PDF files on a network share... and run your printing code on the same machine which provides the share... ideally the printer is directly connected to that machine... this should provide enough performance and since it is only one central application accessing the printer it should work fine...
I would strongly recommend the use of a PDF library or Acrobat reader so that the printing can use a parameter for NumberOfCopies !
EDIT 2 - as per comment:
Some PDF Libraries:
.NET library to print PDF files
http://www.gnostice.com/PDFOne_dot_NET.asp
http://www.gdpicture.com/products/dotnet/plugins/pdf-plugin.php
http://itextpdf.com/

Problem launching a System.Diagnostics.Process under Windows 7

I’m trying to launch an application (Operating System, My Application and the application I want to launch are all 32 bits), from .NET 3.51.
The code that launches the Process is used for other applications, but there’s one that is giving us a headache. If we “double click” on the application’s icon, it works as expected, meaning that it works fine as an application in the computer. Double clicking the .exe directly, also works.
The operating system is Windows 7 32Bits (Home and/or Professional).
Our .NET application is compiled with x86 to avoid problems.
The code that launches “Processes” is located inside a DLL (also 32 bits) made by us, basically it’s a simple DLL that holds some “Common Code” across the board, common methods, functions and stuff we use throughout our code. One of those methods look like this:
public static bool FireUpProcess( Process process, string path, bool enableRaisingEvents,
ProcessWindowStyle windowStyle, string arguments )
{
if ( process != null )
{
try
{
process.StartInfo.FileName = #path;
if ( arguments != null )
{
if ( arguments != String.Empty )
{
process.StartInfo.Arguments = arguments;
}
}
process.StartInfo.WindowStyle = windowStyle;
process.EnableRaisingEvents = enableRaisingEvents;
process.Start();
}
catch
{
try
{
process.Kill();
}
catch ( InvalidOperationException )
{
} // The process is not even created
return false;
}
}
else
{
return false;
}
return true;
}
I don’t know who wrote this method, but it has been working for roughly six years with different applications, therefore I assume it’s “ok”. However, we have a customer with a piece of software that won’t launch when passed through that argument.
The arguments are:
process is a System.Diagnostics.Process created with a simple "new Process();”
path is a full path to the .exe “c:/path/to/my.exe”.
enableRaisingEvents is false
windowStyle is Maximized (but have tried others).
It gives a crappy MessageBox… which I have happily immortalized. It’s in spanish but the translation ought to be easy:
It says:
Application Error
An unexpected exception has occurred for the program (0x0eedfade) at …
Googling that 0x0eedfade gives strange results that look scary, but the truth is, if I go to the .exe that I’m trying to launch and double click it, it works perfectly.
For The Record: If I try to launch other things (I.e.: Notepad.exe, Adobe Acrobat Reader) it works, but Firefox doesn’t open and doesn’t show an error.
This “some work, some doesn’t” behavior leads me to believe that there might be a problem with a Windows 7 security mechanism or similar that I don’t know.
What am I missing or doing wrong?
UPDATE: Ok; I’ve gotten a copy of the software. It’s a messy software but it works. Now that I can debug, I see that the program gives an error when launched with my FireUpProcess method.
As suggested I added the WorkingDirectory code, but here’s the code:
public static bool FireUpProcess(Process process, string path, bool enableRaisingEvents, ProcessWindowStyle windowStyle)
{
if (process != null)
{
try
{
if ( !String.IsNullOrEmpty(#path) )
{
process.StartInfo.FileName = #path;
process.StartInfo.WorkingDirectory = System.IO.Path.GetDirectoryName(#path);
process.StartInfo.WindowStyle = windowStyle;
// Suscribe to the exit notification
process.EnableRaisingEvents = enableRaisingEvents;
// Disable to prevent multiple launchs
Framework.Check.LogWarning("LAUNCHING EXTERNAL DEVICE WITH PATH: " + path);
process.Start(); // HERE The program reports the following:
That means, “The program could not be started because ddip.dll is missing… try reinstalling bla bla”.
The thing is, if I execute the same #path from the command line, the program opens perfectly:
That opens the program. And the same happens if I click on the “shortcut” that it’s located in the “programs” menu. There aren’t any parameters in that shortcut, it’s a simple call to the executable file.
So the question is now: What is the difference between my code and the other methods?
There has got to be something different that causes my process not to start.
Any ideas?
UPDATE AND SOLUTION
I made it work by using one of the below provided answers. Turns out that none directly pointed me to the solution, but they all gave me good ideas here and there.
I added an app manifest to our application (should have had it since the age of vista, don’t know why it wasn’t there in the 1st place). The app manifest I added by using VStudio 2008 add file -> app manifest.
In it, I made sure we have this:
<requestedExecutionLevel level=“asInvoker” uiAccess=“false” />
We don’t need admin or anything like that, but apparently Vista/7 need to know it.
After that was added, the process is correctly launched.
note: UseShellExecute is true by default (as suggested by some), you have to explicitly turn it to false if that’s what you want.

You are not setting the process.StartInfo.WorkingDirectory property. There's plenty of poorly written software out there that assumes the working directory will be the directory in which the EXE is stored. At least add this line:
process.StartInfo.WorkingDirectory = System.IO.Path.GetDirectoryName(#path);
The exception is however rather strange. I'd definitely recommend you tell the customer to update their anti-malware tools.

If the exe has a manifest, you should set UseShellExecute to true on the process object before you call Start. It's not a bad idea in any case.

As Kate Gregory pointed out, if you want to "emulate" the user double clicking on the icon, you have to set UseShellExecute to true. Setting this flags make the code use a totally different path, using the underlying windows ShellExecute function.
Now, I will add to this, that if you're running on a UAC-equipped Windows (Vista, 7, 2008, ...) you maybe should also try to use the runas verb as explained here and here.
With .NET, that would be:
if (System.Environment.OSVersion.Version.Major >= 6) // UAC's around...
{
processStartInfo.Verb = "runas";
}

I've had similar problems in the past. I resolved it by executing the cmd app as follows:
public static bool FireUpProcess(Process process, string path, bool enableRaisingEvents, ProcessWindowStyle windowStyle)
{
//if path contains " ", surround it with quotes.
//add /c and the path as parameters to the cmd process.
//Any other parameters can be added after the path.
ProcessStartInfo psi = new ProcessStartInfo("cmd", "/c" + path ));
psi.WorkingDirectory = System.IO.Path.GetDirectoryName(#path);
psi.WindowStyle = windowStyle;
// Suscribe to the exit notification
process.EnableRaisingEvents = enableRaisingEvents;
// Disable to prevent multiple launchs
Framework.Check.LogWarning("LAUNCHING EXTERNAL DEVICE WITH PATH: " + path);
process.Start(); ...}

If it is possible I would try to use Process Monitor from Sysinternals. When you start it up you can deselect Registry and Network Activity on the toolbar (the 5 icons on the right side). Then you only see Process and Disk activity. Since it looks like a file not found problem you should use the Filter dialog (6. icon from the left) select Process Name from the Drop down list (Architecture is the default) and enter your failing executable name. This will greatly limit the captured output so you can see what is going on. Then start the exectuable and check in the Result Column for NAME NOT FOUND result. This are the locations where a file was searched but not found. If you know the offending dll name you can search for it with Ctrl+F as usual to dig it out. Then you can compare the different search paths from your working application and when it was started from your application.
Could it be that the environment variable PATH has a different value inside your process? It could be that adding . (the current directory) helps to fix the dll search path. Or is the application started from a different user account? It could also be the new feature that when an application is installing things into Programm Files but has no rights (only administrator can do this) Windows will redirect the writes into the user profile. This is a secure and transparent way to get more secure. But this could cause e.g. during first application startup some e.g. config file to be deployed into the Administrators Profile when he is running the application not with consent from the UAC dialog. Then other users might also start the application but fail because the additional config file is located in the Administrators profile and not in Program Files as expected for everyone.

I believe Hans Passant is on the right track. In addition to what he said, check to ensure that ddip.dll and the exe are in the same directory. This is not always the case as there are other ways to bind assemblies outside the bin. Namely, the GAC and AssemblyResolve event. Considering your situation I see no reason the GAC is involved. Check the exe's code that is launched for any hooks into the AssemblyResolve event. If it's hooked into you may need to update the implementation to allow another process to launch it.
Because you are getting an exception regarding a missing DLL, I have little confidence in the answers regarding path delimiter issues. Nonetheless, you have the application code, so verify that it references ddip.dll. This will give you a good deal of confidence that you are in fact referencing the correct .exe and therefore it's not just a path delimiter problem with the command prompt (E.G. misinterpreted spaces).

Java and .net interoperability

I have a c# program through which i am opening cmd window as a a process. in this command window i am running a batch file. i am redirecting the output of that batch file commands to a Text File. When i run my application everything seems to be ok.
But few times, Application is giving some error like "Can't access the file. it's being used by another application" at the same time cmd window is not getting closed. If we close the cmd process through the Task Manager, then it's writing the content to the file and getting closed. Even though i closed the cmd process, still file handle is not getting released. so that i am not able to run the application next time onwards.Always it's saying Can't access the file. Only after restarting the system, it's working.
Here is my code:
Process objProcess = new Process();
ProcessStartInfo objProInfo = new ProcessStartInfo();
objProInfo.WindowStyle = ProcessWindowStyle.Maximized;
objProInfo.UseShellExecute = true;
objProInfo.FileName = "Batch file path"
objProInfo.Arguments = "Some Arguments";
if (Directory.Exists(strOutputPath) == false)
{
Directory.CreateDirectory(strOutputPath);
}
objProInfo.CreateNoWindow = false;
objProcess.StartInfo = objProInfo;
objProcess.Start();
objProcess.WaitForExit();
test.bat:
java classname argument > output.txt
Here is my question:
I am not able to trace where the problem is..
How we can see the process which holding handle on ant file.
Is there any suggestions for Java and .net interoperability

In situations like this I start up the Process Explorer ( by Sysinternals, awesome tool btw ) click Ctrl+F, and enter the name of the file. It will search across all running processes and will list the file handles to this file by the applications that have it open.
You can then either drop the handle, or kill the app - whatever you think is better )

You can try forking and attaching file descriptor from C# rather than launching a bat file.

I think the problem is because the java program is accessing the text file when the C# program is writing something on it, and hence a "file cannot access" problem.
If I were you, I would do everything in C#-- I won't use Java to read the state of the C# program. And I would access the file only after I've completed whatever the C# needs to do.
As for to see what process is locking up your file, you can use Process Explorer for this purpose.

If I have the URL of a torrent, how can I just "launch" it using the Process.Start()?

I found a way to obtain the URL of a torrent file, if I have this in string format, is there a way for me to just launch it whenever a user presses a button in my app?
I know I could save the file and then call it up, but I'd rather just open it. Is this possible?

You can just start it, but what will happen then is your default browser will open and it will download the file. And depending on the local settings on that machine it will do the default thing.
I would not recommend this method, it means the end user will have to do alot of extra steps. And the different browsers behave differently, and may not obey windows file extentions ( thing firefox )
If your doing this inside a application you should download it yourself, you can read about that here. .NET Frameworks offers great solutions to download the file yourself.
Also if you do it via Proccess you will not get a refere when downloading, some sites may then block you to stop hot linking. but if you control the download class you can send a refere url

Don't know if this is OK for you, but if you have the torrent protocol registered to an installed application, simply launching the URL as if it were the path of an executable file (for example by using the Process class) will launch the associated application. See here: http://kb.mozillazine.org/Register_protocol

Try this:
Process p = new Process();
p.StartInfo.FileName = "http://domain/folder/file.torrent";
p.Start();
Or, if you like one-liners:
new Process
{
StartInfo = new ProcessStartInfo
{
FileName = "http://domain/folder/file.torrent"
}
}.Start();
That will call your default browser to download that file and tries to open it. Clicking "Open" you associate program takes control.