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Regular Expression For File Name in C#

I am trying to find a regular expression to parse two sections out of the file name for the .resx files in my project. There is one main file called "UiText.resx" and then many translation .resx files with convention "UiText.ja-JP.resx". I need both the "UiText" and the "ja-JP" out of the latter string, as we do have other resx files that don't have to be for UiText (e.g. I have some files named "ExceptionText.resx").
The pattern I'm using right now (which works, it just requires a little extra coding after) is "(?<=\.)((.*?)(?=\.resx))". For the example above, "UiText.ja-JP.resx" gets me a match set in C# of "UiText.", "ja-JP.", "ja-JP.", ".resx"
Of course I am able to just take the first occurrence of "ja-JP." and "UiText." from this set and massage it to what I want, but I'd rather just have a cleaner "UiText" "ja-JP" and be done with it.
I figure I'll probably have to have at least two different patterns for this, so that is OK. Thank you in advance!

Since UiText seems to be constant you can use this regex to extract just js-JP into $1:
^UiText\.(.+?)\.resx$
https://regex101.com/r/XKvwHA/1/

If I'm understanding your needs correctly, then the main reason you need "UiText" is not because you have any value for the term itself, but rather because you need to filter your files. The real term you need to play around with is "ja-JP", which changes for the files you need.
If I'm correct, try this regex:
(?<=UiText\.).+(?=\.resx)
Used in C# as follows:
var fileName = "UiText.ja-JP.resx";
var result = new Regex(#"(?<=^UiText\.).+(?=\.resx$)").Match(fileName).Value;
A little explanation:
(?<=^UiText\.) Start of string must begin exactly with "UiText."
.+ Any number of characters (but at least one)
(?=\.resx$) End of string must end with ".resx"
Any file that doesn't meet your criteria will return an empty string for 'result'.

Replace beginning and end of string with unique midle?

I have lots of code like below:
PlusEnvironment.EnumToBool(Row["block_friends"].ToString())
I need to convert them to something like this.
Row["block_friends"].ToString() == "1"
The value that gets passed to EnumToBool is always unique, meaning there is no guarantee that itll be passed by a row, it could be passed by a variable, or even a method that returns a string.
I've tried doing this with regex, but its sort of sketchy and doesn't work 100%.
PlusEnvironment\.EnumToBool\((.*)\)
I need to do this in Visual Studio's find and replace. I'm using VS 17.

If you had a few places where PlusEnvironment.EnumToBool() was called, I would have done the same thing that #IanMercer suggested: just replace PlusEnvironment.EnumToBool( with empty string and the fix all the syntax errors.
#IanMercer has also given you a link to super cool, advanced regex usage that will help you.
But if you are skeptical about using such a complex regex on hundreds of files, here is what I would have done:
Define my own PlusEnvironment class with EnumToBool functionality in my own namespace. And then just replace the using Plus; line with using <my own namespace>; in those hundreds of files. That way my changes will be limited to only the using... line, 1 line per file, and it will be simple find and replace, no regex needed.
(Note: I'm assuming that you don't want to use PlusEnvironment, or the complete library and hence you want to do this type of replacement.)

in Find and Replace Window:
Find:
PlusEnvironment\.EnumToBool\((.*))
Replace:
$1 == "1"
Make sure "Use Regular Expressions" is selected

Escaping directory chars in C#

I need to escape chars in a string I have, which content is C:\\blablabla\blabla\\bla\\SQL.exe to C:\blablabla\blabla\bla\SQL.exe so I could throw a process based on this SQL.exe file.
I tried with Mystring.Replace("\\", #"\"); and Mystring.Replace(#"\\", #"\"); but none worked.
How could I do this?
EDITED: Corrected type in string.

I very strongly suspect that you are looking this input string in the Visual Studio debugger and fooling yourself that there are actually 2 \ whereas in reality there aren't. That's the reason why attempting to replace \\ with \ doesn't do anything because in the original string there is no occurrence of \\. And since you are looking the output once again in the debugger, you are once again fooling yourself that there are 2 \.
Visual Studio debugger has this tendency to escape strings. Log it to a file or print to the console and you will see that there is a single \ in your input string and you don't need to replace anything.

It looks like you're trying to replace double backslash (#"\\") in a string with single backslash (#"\"). If so try the following
Mystring = Mystring.Replace(#"\\", #"\");
Note: Are you sure that the string even contains double backslashes? Certain environments will print out a single backslash as a double (debugger for example). Your comment mentioned my approach didn't work. That's a flag that there's not actually a double backslash in your string (else it would work).

The # character specifies a string as a verbatim literal string, but that is when constructing a string. If you use Mystring.Replace("\\", #"\") then nothing will be replaced, essentially, as the two strings are the same.
If you want a string without the escape characters, then either define it with:
string path = #"C:\Some\Directory\And\File.txt";
Or you can replace the \\ with / like so:
path = path.Replace('\\', '/');
It is worth noting, as mentioned by Darin Dimitrov, that the string containing two \ characters is likely just the display of the string (i.e. when using the debugger) and not the actual value of the string.

i think OP is asking how to escape \\ in File Path, if that in the case, as OP is not mentioning where he's trying to use this. so i'm putting a guess.
Then You use Path.Combine() method to get the FileName path.
Path.Combine() Documentation

where are you looking at this output? because it could be the string is what you expect, but viewing the value through the debugger, output window, etc. is escaping the slash

Use something like:
myStr = myStr.Replace(#"\\", #"\");
Make sure you assign the result of Replace method to myStr. Otherwise it goes into void ;)

Try adding "|DataDirectory|\MyFile.xyz" where you need it. It works with connection strings it might work with something else (I haven't really tried to apply it to something else).

I didn't understand what you want, if you just want do get the file name (escape directory chars) you can try:
string fileName = Path.GetFileName(YourString)

Noloman.... when you concatenate are you perhaps missing a "\" when concatenating the directory.. I am assuming that you are trying to join directory + some sub directory.. #noloman keep in mind that in C# "c:\Temp" is written like this "c:\Temp" or #"c:\Temp" one is Literal the other is how to represent a "\" in the legacy way of coding because the "\" is an escape Char and when dealing with directorys we represent all paths and sub paths with "\"
so perhaps by you replacing the "\" you are truly messing up your own expected process
Mystring = Mystring.Replace(#"\\", #"\");
should work for you unless you are truly meaning to do
Mystring = Mystring.Replace(#"\", "\"); which if you believe that you are expecting a "\" to be used to build the directory.. then of course it will not work.. because you have just in essense replaced the backslash with a return char.. I hope that this makes sense to you..
System.IO.Directory.GetCurrentDirectory(); you are using is also an Issue.. SQL Server is not that application thats running the code.. it's your .NET application so you need to either put the location of the SQL Server into a variable, app.config, web.config ect... please edit your question and paste the code that you are using to do what it is that you want to do inregards to the SQL Server Code.. you would probably want to look at the Are you wanting to do something like Process.Start(....) meaning the file name..?

How do I find the parent directory in C#?

I use this code for finding the debug directory
public string str_directory = Environment.CurrentDirectory.ToString();
"C:\\Users\\Masoud\\Documents\\Visual Studio 2008\\Projects\\MyProj\\MyProj\\bin\\Debug"
How can I find the parent folder as shown below?
"C:\\Users\\Masoud\\Documents\\Visual Studio 2008\\Projects\\MyProj\\MyProj"

You can use System.IO.Directory.GetParent() to retrieve the parent directory of a given directory.

string parent = System.IO.Directory.GetParent(str_directory).FullName;
See BOL

If you append ..\.. to your existing path, the operating system will correctly browse the grand-parent folder.
That should do the job:
System.IO.Path.Combine("C:\\Users\\Masoud\\Documents\\Visual Studio 2008\\Projects\\MyProj\\MyProj\\bin\\Debug", #"..\..");
If you browse that path, you will browse the grand-parent directory.

Edit: The normalization covered in this answer only happens when the path is used to access the file system, but not on the string itself. By contrast, this answer achieves the result and normalization purely using path strings, without using the file system at all.
I've found variants of System.IO.Path.Combine(myPath, "..") to be the easiest and most reliable. Even more so if what northben says is true, that GetParent requires an extra call if there is a trailing slash. That, to me, is unreliable.
Path.Combine makes sure you never go wrong with slashes.
.. behaves exactly like it does everywhere else in Windows. You can add any number of \.. to a path in cmd or explorer and it will behave exactly as I describe below.
Some basic .. behavior:
If there is a file name, .. will chop that off:
Path.Combine(#"D:\Grandparent\Parent\Child.txt", "..") => D:\Grandparent\Parent\
If the path is a directory, .. will move up a level:
Path.Combine(#"D:\Grandparent\Parent\", "..") => D:\Grandparent\
..\.. follows the same rules, twice in a row:
Path.Combine(#"D:\Grandparent\Parent\Child.txt", #"..\..") => D:\Grandparent\
Path.Combine(#"D:\Grandparent\Parent\", #"..\..") => D:\
And this has the exact same effect:
Path.Combine(#"D:\Grandparent\Parent\Child.txt", "..", "..") => D:\Grandparent\
Path.Combine(#"D:\Grandparent\Parent\", "..", "..") => D:\

To get a 'grandparent' directory, call Directory.GetParent() twice:
var gparent = Directory.GetParent(Directory.GetParent(str_directory).ToString());

Directory.GetParent is probably a better answer, but for completeness there's a different method that takes string and returns string: Path.GetDirectoryName.
string parent = System.IO.Path.GetDirectoryName(str_directory);

Like this:
System.IO.DirectoryInfo myDirectory = new DirectoryInfo(Environment.CurrentDirectory);
string parentDirectory = myDirectory.Parent.FullName;
Good luck!

No one has provided a solution that would work cross-form. I know it wasn't specifically asked but I am working in a linux environment where most of the solutions (as at the time I post this) would provide an error.
Hardcoding path separators (as well as other things) will give an error in anything but Windows systems.
In my original solution I used:
char filesep = Path.DirectorySeparatorChar;
string datapath = $"..{filesep}..{filesep}";
However after seeing some of the answers here I adjusted it to be:
string datapath = Directory.GetParent(Directory.GetParent(Directory.GetCurrentDirectory()).FullName).FullName;

You might want to look into the DirectoryInfo.Parent property.

IO.Path.GetFullPath(#"..\..")
If you clear the "bin\Debug\" in the Project properties -> Build -> Output path, then you can just use AppDomain.CurrentDomain.BaseDirectory

Since nothing else I have found helps to solve this in a truly normalized way, here is another answer.
Note that some answers to similar questions try to use the Uri type, but that struggles with trailing slashes vs. no trailing slashes too.
My other answer on this page works for operations that put the file system to work, but if we want to have the resolved path right now (such as for comparison reasons), without going through the file system, C:/Temp/.. and C:/ would be considered different. Without going through the file system, navigating in that manner does not provide us with a normalized, properly comparable path.
What can we do?
We will build on the following discovery:
Path.GetDirectoryName(path + "/") ?? "" will reliably give us a directory path without a trailing slash.
Adding a slash (as string, not as char) will treat a null path the same as it treats "".
GetDirectoryName will refrain from discarding the last path component thanks to the added slash.
GetDirectoryName will normalize slashes and navigational dots.
This includes the removal of any trailing slashes.
This includes collapsing .. by navigating up.
GetDirectoryName will return null for an empty path, which we coalesce to "".
How do we use this?
First, normalize the input path:
dirPath = Path.GetDirectoryName(dirPath + "/") ?? ""; // To handle nulls, we append "/" rather than '/'
Then, we can get the parent directory, and we can repeat this operation any number of times to navigate further up:
// This is reliable if path results from this or the previous operation
path = Path.GetDirectoryName(path);
Note that we have never touched the file system. No part of the path needs to exist, as it would if we had used DirectoryInfo.

To avoid issues with trailing \, call it this way:
string ParentFolder = Directory.GetParent( folder.Trim('\\')).FullName;

To get your solution
try this
string directory = System.IO.Directory.GetParent(System.IO.Directory.GetParent(Environment.CurrentDirectory).ToString()).ToString();

This is the most common way -- it really depends on what you are doing exactly:
(To explain, the example below will remove the last 10 characters which is what you asked for, however if there are some business rules that are driving your need to find a specific location you should use those to retrieve the directory location, not find the location of something else and modify it.)
// remove last 10 characters from a string
str_directory = str_directory.Substring(0,str_directory.Length-10);

You shouldn't try to do that. Environment.CurrentDirectory gives you the path of the executable directory. This is consistent regardless of where the .exe file is. You shouldn't try to access a file that is assumed to be in a backwards relative location
I would suggest you move whatever resource you want to access into a local location. Of a system directory (such as AppData)

In my case I am using .NET 6. When I use:
public string str_directory = Environment.CurrentDirectory.ToString();
returns C:\Projects\MyTestProject\bin\Debug\net6.0
In order to reach C:\Projects\MyTestProject I am using the following:
Directory.GetParent(Directory.GetCurrentDirectory()).Parent.Parent
You can chain Parent to Directory.GetParent(Environment.CurrentDirectory) in order to reach the directory you want.
Final version:
public string str_directory = Directory.GetParent(Environment.CurrentDirectory).Parent.Parent.ToString();

formatting strings with backslash

I'm a newbie to c# so hopefully this one isn't too hard for a few of you.
I'm trying to build a string that has a \ in it and I am having difficulty getting just one backslash to show up even though I am adding additional escape chars or ignoring them all together. Can someone show me what I am doing wrong?
What I want my string to look like:
"10.20.14.103\sql08"
What I've tried so far:
I added an additional character to make the compiler happy but it did not escape it.
ip = string.Format("{0}\\\\{1}", ip, instancename); // output has 2 \'s
I told it to ignore escapes, it decided to ignore me instead
string temp = #"192.168.1.200\sql08"; // output has 2 \'s
Can someone help me make sense of this? (The richtext editor here seems to do a better job with it than VS2010 is doing, lol)

I'm guessing you're getting confused by the debugger.
If you hover your mouse over a local variable in VS, strings will be escaped so a single \ will display as \\.
To see what your string really is, output it somewhere for display (e.g., to the console) or hover your mouse on the variable, click on the arrow next to the little magnifying glass that appears, and select "Text Visualizer."

If you're looking at these strings in the debugger (i.e., by hovering the mouse over the variable or using a watch), the debugger adds escape characters to the display string so that it's a valid string expression. If you want to view the string verbatim in this fashion, click on the magnifying glass on the right side of the tooltip or watch entry with the string in it.

I'm guessing you're looking at the values in the debugger and seeing that they have two slashes.
That's normal. The debugger will show two slashes even though the actual string representation will only have one. Just another hump to get over when getting used to the debugger.
Be assured that when you actually use your strings, they will still only have a single slash (using either of your methods).

string requiredString = string.Format(#"{0}\\{1}",str1,str2);