Develop Reference

Calling a Python script from C# - changing the script's filepath causes the program to not work

The following code works perfectly without flaw:
public partial class MainForm : Form
{
string pyInterp = File.ReadAllText(Directory.GetCurrentDirectory() + #"\config\pathToPythonInterpreter.txt");
string pyWeather = #"C:\getWeather.py";
public MainForm()
{
InitializeComponent();
UpdateWeather();
}
public void UpdateWeather()
{
labelWeather.Text = PySharp.ExecutePy(pyInterp, pyWeather);
}
}
However, when I change the path to getWeather.py to not be in an arbitrary random location, like this:
string pyWeather = Directory.GetCurrentDirectory() + #"\scripts\getWeather.py";
Then my program no longer obtains the script's output. The script still works: I launched it using IDLE and it completed its function properly. When I call it using C#, the console opens, yet no output is obtained.
The Python script is the following:
from requests import get
from bs4 import BeautifulSoup as soup
r = get("http://www.ilmateenistus.ee/ilm/prognoosid/4-oopaeva-prognoos/")
parsed = soup(r.content, "html.parser")
container = parsed.find("div",{"class":"point kuusiku"})
print(str(container["data-title"]))
(It webscrapes my local weather)
PySharp.ExecutePy() can be viewed here
By far the strangest bug I've ever encountered. Any ideas?
EDIT 1: It seems that C# is indeed reading something from the script. It just appears that this something is.. nothing. I gave the label a default sample text, and after running the program, the label's text is simply changed to an empty string. Hope this incredible discovery helps somehow.
EDIT 2: The program fails to call the script correctly when its filepath contains spaces. For example:
C:\foo bar\testing\pyWeather.py
does not work!

Try surrounding the path that contains spaces with 2 double quotes.
For e.g.
string pyWeather = #"""C:\Users\[myname]\Documents\Visual Studio 2017\Projects\testing\testing\scripts\getWeather.py""";
Similarly, you can do string pyWeather = Directory.GetCurrentDirectory() + #"\scripts\getWeather.py"; followed by pyWeather = "\"" + pyWeather + "\"";.

I would want you to return the answer instead of printing. Printer is an I/O based solution to display. So it will work super fine with IDLE however it may not return results as you expected. I strongly believe this will solve your problem.
instead of printing please try return. I can give more support after trying this.
return(str(container["data-title"]))

Build visual studio solution using msbuild from c# code

I want to build my solution file from other c# code using msbuid I have tried
var msbuild_path = #"C:\Windows\Microsoft.NET\Framework\v4.0.30319\msbuild.exe";
var solution_path = #"D:\Sumit\WorkingCopy\Final\Final.sln";
Process.Start(msbuild_path + " " + solution_path);
but this one throws an error Please help me out!!

According to https://msdn.microsoft.com/en-us/library/h6ak8zt5(v=vs.110).aspx , the Process.Start method takes two arguments:
public static Process Start(string fileName, string arguments)
So you should change your code to
Process.Start(msbuild_path, solution_path);
What you were doing before was actually trying to run a file named "C:\Windows\Microsoft.NET\Framework\v4.0.30319\msbuild.exe(space)D:\Sumit\WorkingCopy\Final\Final.sln", but no such file exists with that name. The msbuild.exe may exist, but "msbuild.exe D:\Sumit...\Final.sln" is not the filename you meant to pass as the command filename. Also, the argument string was empty, so the system assumed you did not want to pass any arguments to "msbuild.exe D:\Sumit...\Final.sln". But the error message was because the two filenames were mashed into one filename.
Windows allows filenames to contain embedded spaces, which frequently causes problems in dealing with command-line arguments.

Why can't i use this code to make a minecraft launcher in c#?

I have searched everywhere to find out how to make a custom minecraft launcher. I managed to create this code, which should work, but sadly it does not. I login but it never starts, however for a second I get the loading ring next to my mouse. This is my code:
ProcessStartInfo start = new ProcessStartInfo();
// Enter in the command line arguments, everything you would enter after the executable name itself
start.Arguments = #"-Xmx1G -Djava.library.path=%APPDATA%\.minecraft\versions\1.6.2\1.6.2-natives -cp %APPDATA%\.minecraft\libraries\net\sf\jopt-simple\jopt-simple\4.5\jopt-simple-4.5.jar;%APPDATA%\.minecraft\libraries\com\paulscode\codecjorbis\20101023\codecjorbis-20101023.jar;%APPDATA%\.minecraft\libraries\com\paulscode\codecwav\20101023\codecwav-20101023.jar;%APPDATA%\.minecraft\libraries\com\paulscode\libraryjavasound\20101123\libraryjavasound-20101123.jar;%APPDATA%\.minecraft\libraries\com\paulscode\librarylwjglopenal\20100824\librarylwjglopenal-20100824.jar;%APPDATA%\.minecraft\libraries\com\paulscode\soundsystem\20120107\soundsystem-20120107.jar;%APPDATA%\.minecraft\libraries\argo\argo\2.25_fixed\argo-2.25_fixed.jar;%APPDATA%\.minecraft\libraries\org\bouncycastle\bcprov-jdk15on\1.47\bcprov-jdk15on-1.47.jar;%APPDATA%\.minecraft\libraries\com\google\guava\guava\14.0\guava-14.0.jar;%APPDATA%\.minecraft\libraries\org\apache\commons\commons-lang3\3.1\commons-lang3-3.1.jar;%APPDATA%\.minecraft\libraries\commons-io\commons-io\2.4\commons-io-2.4.jar;%APPDATA%\.minecraft\libraries\net\java\jinput\jinput\2.0.5\jinput-2.0.5.jar;%APPDATA%\.minecraft\libraries\net\java\jutils\jutils\1.0.0\jutils-1.0.0.jar;%APPDATA%\.minecraft\libraries\com\google\code\gson\gson\2.2.2\gson-2.2.2.jar;%APPDATA%\.minecraft\libraries\org\lwjgl\lwjgl\lwjgl\2.9.0\lwjgl-2.9.0.jar;%APPDATA%\.minecraft\libraries\org\lwjgl\lwjgl\lwjgl_util\2.9.0\lwjgl_util-2.9.0.jar;%APPDATA%\.minecraft\versions\1.6.2\1.6.2.jar net.minecraft.client.main.Main --username playername --session token:"+ words[3] + #":" + words[4]+ #" --version 1.6.2 --gameDir %APPDATA%\.minecraft --assetsDir %APPDATA%\.minecraft\assets";
start.FileName = #"c:\Program Files (x86)\java\jre7\bin\javaw.exe";
// Do you want to show a console window?
start.CreateNoWindow = true;
System.Diagnostics.Process.Start(start);
This just does the loading ring by my mouse for a second, then nothing opens. No logs, crashes, errors, nothing wrong. This is Visual c# compiled on Visual Studio 2012.

The arguments you are giving have an environment variable in them - %APPDATA%.
The command line will expand this by default, but the .net library won't.
See How do I ensure c# Process.Start will expand environment variables?

As Pete Kirkham mentioned you need to set up environment variable.
You can set it before starting the Process like:
var appDataPath = "your path";
start.EnvironmentVariables.Add("APPDATA", appDataPath);

Displaying command in cmd console

I'm trying to run a command in cmd using C# and am having some difficulties. I'd like to be able to write the command to the cmd console so I can see what it's trying to run (I think there's some issue with the quotes or something, so if I could see the actual string in the command line, I'd be able to see exactly what the problem is). My code looks like this:
var processStartInfo = new ProcessStartInfo("cmd", "/c"+commandString);
processStartInfo.CreateNoWindow = true;
Process.Start(processStartInfo);
So basically, I just want to see the string commandString written in the console. Any help would be greatly greatly appreciated.
string CommandLineString = #"""C:\Program Files\Microsoft SQL Server\100\Tools\Binn\bcp.exe"" ""SELECT * FROM table where date >= '2009-01-01'"" queryout ""C:\Data\data.dat"" -S DBSW0323 -d CMS -n -T";

In this case, the problem is probably just your lack of a space after "/c".
var processStartInfo = new ProcessStartInfo("cmd", "/c " + commandString);
As for viewing in a command window, instead, you will probably be better off inspecting the Arguments property of your processStartInfo instance.
EDIT
Taking into account the command line details you posted, I believe this is what your issue is. Check out the following from cmd help:
If /C or /K is specified, then the remainder of the command line after
the switch is processed as a command line, where the following logic is
used to process quote (") characters:
If all of the following conditions are met, then quote characters
on the command line are preserved:
no /S switch
exactly two quote characters
no special characters between the two quote characters,
where special is one of: &<>()#^|
there are one or more whitespace characters between the
the two quote characters
the string between the two quote characters is the name
of an executable file.
Since you are using /c, you have quote and special char issues still. Try wrapping your entire commandString in a set of quotes.
Take this simple example for instance (creating temp.txt manually of course):
string commandString = #"""C:\WINDOWS\Notepad.exe"" ""C:\temp.txt""";
var processStartInfo = new ProcessStartInfo("cmd", "/c " + commandString);
The command line to be executed will be: /c "C:\WINDOWS\Notepad.exe" "C:\temp.txt", but this will fail since "C:\temp.txt" is not an executable.
If you wrap the whole thing in one last set of quotes, you should see the intended result:
string commandString = #"""""C:\WINDOWS\Notepad.exe"" ""C:\temp.txt""""";
var processStartInfo = new ProcessStartInfo("cmd", "/c " + commandString);
Resulting in a command line of: /c ""C:\WINDOWS\Notepad.exe" "C:\temp.txt"" and ultimately opening notepad with your test file.

That string is not "written" to the console, it's part of the argument list for a program you launch (which in this case happens to be cmd.exe). Since the console created is owned by that program, unless it wants to print its arguments for its own reasons (which it won't) this is not directly doable.
If you simply want to debug then why not inspect the value of commandString, or write it out into a log file?
If you absolutely need the command line to be displayed in the console then you could resort to hacks (run another intermediate program that prints the command line and then calls cmd.exe with it), but unless there is some other good reason to use this approach I would not recommend it.

Using Javac in C#?

Okay, so I've been working on this a while (and I've gone through multiple questions to get this far in the project).
Here's the C# code I'm using:
Process p = new Process();
p.StartInfo.RedirectStandardError = true;
p.StartInfo.UseShellExecute = false;
p.StartInfo.FileName = "javac";
Directory.CreateDirectory(Path.Combine(Application.StartupPath + #"\TempJavaalfgwaepfgawe"));
p.StartInfo.Arguments = "-d " + Path.Combine(Application.StartupPath + #"\TempJavaalfgwaepfgawe") + " " + files;
p.Start();
p.WaitForExit();
MessageBox.Show(p.StandardError.ReadToEnd());
In essence, I am trying to invoke the Java compiler (javac) from a C# application.
Now, when I do this, it wasn't compiling the java code correctly, so I inserted the RedirectStandardError and UseShellExecute as well as the WaitForExit and MessageBox at the end to see the error that was occurring.
Anyways, the error is as follows:
javac: invalid flag: 2010\Projects\Java
Usage: javac [options] [source files]
use -help for a list of possible options
So, what's wrong with my code?
To me, the error looks like part of the location of one of the file paths.

I suggested the fix in the comments, but I also wanted to add a formal answer for others with this problem.
When you pass in arguments to a process, strings that have spaces need to be quoted. This tells the argument parser that you really mean one argument. (different arguments are usually divided by white space)