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Extract a pattern from a group of filenames and place into listbox

I have a folder with a lot of files like this:
2016-01-02-03-abc.txt
2017-01-02-03-defjh.jpg
2018-05-04-03-hij.txt
2022-05-04-03-klmnop.jpg
I need to extract the pattern from each group of filenames.
For example, I need the pattern 01-02-03 from the first two files placed in a list. I also need the pattern 05-04-03 placed in the same list. So, my list will look like this:
01-02-03
05-04-03
Here is what I have so far. I can successfully remove the characters but getting one instance of a pattern back into a list is beyond my pay grade:
public void GetPatternsToList()
{
//Get all filenames with characters removed and place in listbox.
List<string> files = new List<string>(Directory.EnumerateFiles(folderBrowserDialog1.SelectedPath));
foreach (var file in files)
{
var removeallbeforefirstdash = file.Substring(file.IndexOf("-") + 1); // removes everthing before the dash in the filename
var finalfile = removeallbeforefirstdash.Substring(0,removeallbeforefirstdash.LastIndexOf("-")); // removes everything after dash in name -- will crash if file without dash is in folder (not sure how to fix this either)
string[] array = finalfile.ToArray(); // I need to do the above with each file in the list and then place it back in an array to display in a listbox
List<string> filesList = array.ToList();
listBox1.DataSource = filesList;
}
}

You could do it this way:
public void GetPatternsToList()
{
var files = Directory.GetFiles(folderBrowserDialog1.SelectedPath);
var patterns = new HashSet<string>();
foreach (var file in files)
{
var splitFileName = file.Split('-').Skip(1).Take(3);
var joinedFileName = string.Join("-", splitFileName);
if(!string.IsNullOrEmpty(joinedFileName)
patterns.Add(joinedFileName);
}
listBox1.DataSource = patterns;
}
I used a HashSet<string> in order to avoid adding duplicate patterns to the DataSource.
A few remarks that aren't related to your question, but your code in general:
I would pass the SelectedPath as a string to the method
I would let the method return you the HashSet
If you implement the above, please also name the method accordingly
All of the above is of course optional for you, but would improve your code quality.

Try this:
public void GetPatternsToList()
{
List<string> files = new List<string>(Directory.EnumerateFiles(folderBrowserDialog1.SelectedPath));
List<string> resultFiles = new List<string>();
foreach (var file in files)
{
var removeallbeforefirstdash = file.Substring(file.IndexOf("-") + 1); // removes everthing before the dash in the filename
var finalfile = removeallbeforefirstdash.Substring(0, removeallbeforefirstdash.LastIndexOf("-")); // removes everything after dash in name -- will crash if file without dash is in folder (not sure how to fix this either)
resultFiles.Add(finalfile);
}
listBox1.DataSource = resultFiles.Distinct().ToList();
}

Check whether a string is in a list at any order in C#

If We have a list of strings like the following code:
List<string> XAll = new List<string>();
XAll.Add("#10#20");
XAll.Add("#20#30#40");
string S = "#30#20";//<- this is same as #20#30 also same as "#20#30#40" means S is exist in that list
//check un-ordered string S= #30#20
// if it is contained at any order like #30#20 or even #20#30 ..... then return true :it is exist
if (XAll.Contains(S))
{
Console.WriteLine("Your String is exist");
}
I would prefer to use Linq to check that S in this regard is exist, no matter how the order is in the list, but it contains both (#30) and (#20) [at least] together in that list XAll.
I am using
var c = item2.Intersect(item1);
if (c.Count() == item1.Length)
{
return true;
}

You should represent your data in a more meaningful way. Don't rely on strings.
For example I would suggest creating a type to represent a set of these numbers and write some code to populate it.
But there are already set types such as HashSet which is possibly a good match with built in functions for testing for sub sets.
This should get you started:
var input = "#20#30#40";
var hashSetOfNumbers = new HashSet<int>(input
.Split(new []{'#'}, StringSplitOptions.RemoveEmptyEntries)
.Select(s=>int.Parse(s)));

This works for me:
Func<string, string[]> split =
x => x.Split(new [] { '#' }, StringSplitOptions.RemoveEmptyEntries);
if (XAll.Any(x => split(x).Intersect(split(S)).Count() == split(S).Count()))
{
Console.WriteLine("Your String is exist");
}
Now, depending on you you want to handle duplicates, this might even be a better solution:
Func<string, HashSet<string>> split =
x => new HashSet<string>(x.Split(
new [] { '#' },
StringSplitOptions.RemoveEmptyEntries));
if (XAll.Any(x => split(S).IsSubsetOf(split(x))))
{
Console.WriteLine("Your String is exist");
}
This second approach uses pure set theory so it strips duplicates.

Filtering strings out of an array

I'm trying to design a check on incoming strings for an array, and if the incoming string has a specific starting character it gets skipped over
For example:
;item1
item2
item3
;item4
should be put into array as
item2
item3
I thought I'd try to use a foreach method to skip the line that starts with the identifier, and then in the else append the lines that don't match back into the string array, but it doesn't seem I am able to do this.
Help!
void Whitelist()
{
if (logging == 1)
{
FIO._Log("Performing WhiteList func", writer);
}
try
{
string[] lines = File.ReadAllLines("Whitelist.ini");
string[] lines2;
foreach (string line in lines)
{
if (line.StartsWith(";"))
{
continue;
}
else
{
// lines2.append(line) ??
}
}
structs.CustomWhiteList = lines2;
}
catch (Exception e)
{
MessageBox.Show("Error reading whitelist file." + Environment.NewLine + e.Message);
FIO._Log("Failed to read whitelist file", writer);
}
}

You can read the lines in, filter out the ones starting with a semicolon, and then set the resulting array directly to CustomWhiteList.
Try the following code:
var lines = File.ReadAllLines("Whitelist.ini");
structs.CustomWhiteList = lines.Where(x => !x.StartsWith(";")).ToArray();
This uses LINQ, so you'll have to add using System.Linq to your class if it's not already there.

C# reading variables into static string from text file

I have seen several posts giving examples of how to read from text files, and examples on how to make a string 'public' (static or const), but I haven't been able to combine the two inside a 'function' in a way that is making sense to me.
I have a text file called 'MyConfig.txt'.
In that, I have 2 lines.
MyPathOne=C:\TestOne
MyPathTwo=C:\TestTwo
I want to be able to read that file when I start the form, making both MyPathOne and MyPathTwo accessible from anywhere inside the form, using something like this :
ReadConfig("MyConfig.txt");
the way I am trying to do that now, which is not working, is this :
public voice ReadConfig(string txtFile)
{
using (StreamReader sr = new StreamResder(txtFile))
{
string line;
while ((line = sr.ReadLine()) !=null)
{
var dict = File.ReadAllLines(txtFile)
.Select(l => l.Split(new[] { '=' }))
.ToDictionary( s => s[0].Trim(), s => s[1].Trim());
}
public const string MyPath1 = dic["MyPathOne"];
public const string MyPath2 = dic["MyPathTwo"];
}
}
The txt file will probably never grow over 5 or 6 lines, and I am not stuck on using StreamReader or dictionary.
As long as I can access the path variables by name from anywhere, and it doesn't add like 400 lines of code or something , then I am OK with doing whatever would be best, safest, fastest, easiest.
I have read many posts where people say the data should stored in XML, but I figure that part really doesn't matter so much because reading the file and getting the variables part would be almost the same either way. That aside, I would rather be able to use a plain txt file that somebody (end user) could edit without having to understand XML. (which means of course lots of checks for blank lines, does the path exist, etc...I am OK with doing that part, just wanna get this part working first).
I have read about different ways using ReadAllLines into an array, and some say to create a new separate 'class' file (which I don't really understand yet..but working on it). Mainly I want to find a 'stable' way to do this.
(project is using .Net4 and Linq by the way)
Thanks!!

The code you've provided doesn't even compile. Instead, you could try this:
public string MyPath1;
public string MyPath2;
public void ReadConfig(string txtFile)
{
using (StreamReader sr = new StreamReader(txtFile))
{
// Declare the dictionary outside the loop:
var dict = new Dictionary<string, string>();
// (This loop reads every line until EOF or the first blank line.)
string line;
while (!string.IsNullOrEmpty((line = sr.ReadLine())))
{
// Split each line around '=':
var tmp = line.Split(new[] { '=' },
StringSplitOptions.RemoveEmptyEntries);
// Add the key-value pair to the dictionary:
dict[tmp[0]] = dict[tmp[1]];
}
// Assign the values that you need:
MyPath1 = dict["MyPathOne"];
MyPath2 = dict["MyPathTwo"];
}
}
To take into account:
You can't declare public fields into methods.
You can't initialize const fields at run-time. Instead you provide a constant value for them at compilation time.

Got it. Thanks!
public static string Path1;
public static string Path2;
public static string Path3;
public void ReadConfig(string txtFile)
{
using (StreamReader sr = new StreamReader(txtFile))
{
var dict = new Dictionary<string, string>();
string line;
while (!string.IsNullOrEmpty((line = sr.ReadLine())))
{
dict = File.ReadAllLines(txtFile)
.Select(l => l.Split(new[] { '=' }))
.ToDictionary( s => s[0].Trim(), s => s[1].Trim());
}
Path1 = dict["PathOne"];
Path2 = dict["PathTwo"];
Path3 = Path1 + #"\Test";
}
}

You need to define the variables outside the function to make them accessible to other functions.
public string MyPath1; // (Put these at the top of the class.)
public string MyPath2;
public voice ReadConfig(string txtFile)
{
var dict = File.ReadAllLines(txtFile)
.Select(l => l.Split(new[] { '=' }))
.ToDictionary( s => s[0].Trim(), s => s[1].Trim()); // read the entire file into a dictionary.
MyPath1 = dict["MyPathOne"];
MyPath2 = dict["MyPathTwo"];
}

This question is similar to Get parameters out of text file
(I put an answer there. I "can't" paste it here.)
(Unsure whether I should "flag" this question as duplicate. "Flagging" "closes".)
(Do duplicate questions ever get consolidated? Each can have virtues in the wording of the [often lame] question or the [underreaching and overreaching] answers. A consolidated version could have the best of all, but consolidation is rarely trivial.)

What's wrong with this ForEach loop?

Yep... it's one of those days.
public string TagsInput { get; set; }
//further down
var tagList = TagsInput.Split(Resources.GlobalResources.TagSeparator.ToCharArray()).ToList();
tagList.ForEach(tag => tag.Trim()); //trim each list item for spaces
tagList.ForEach(tag => tag.Replace(" ", "_")); //replace remaining inner word spacings with _
Both ForEach loops don't work. tagList is just a List.
Thank you!

Trim() and Replace() don't modify the string they're called on. They create a new string that has had the action applied to it.
You want to use Select, not ForEach.
tagList = tagList.Select(t => t.Trim()).Select(t => t.Replace(" ", "_")).ToList();

ForEach (and other "linq" methods) does not modify the list instance.
tagList = tagList.Select(tag => tag.Trim().Replace(" ", "_")).ToList();

The reason is string is immutuable. So the result of each Trim() or Replac() function will produce a new string. You need to reassign to the original element in order to see the updated value.

This is exactly why Microsoft havent implemented ForEach on an IEnumerable. What's wrong with this?
public string[] TagsInput { get; set; }
//further down
var adjustedTags = new List<string>();
foreach (var tag in TagsInput.Split(Resources.GlobalResources.TagSeparator.ToCharArray()))
{
adjustedTags.Add(tag.Trim().Replace(" ", "_"));
}
TagsInput = adjustedTags.ToArray();

If by don't work, you mean that they don't actually do anything, I think you need to adjust your code a bit:
public string TagsInput { get; set; }
//further down
var tagList = TagsInput.Split(Resources.GlobalResources.TagSeparator.ToCharArray()).ToList();
tagList.ForEach(tag => tag = tag.Trim()); //trim each list item for spaces
tagList.ForEach(tag => tag = tag.Replace(" ", "_")); //replace remaining inner word spacings with _
Trim and Replace don't change the value of the string, they return the new string value.