C# - Folder validation

Question

string excludeSubFolders = "SubFolderA, SubFolderB, SubFolderC, SubFolderABC";

DirectoryInfo directory = new DirectoryInfo(myRootFolderPath);
DirectoryInfo[] directories = directory.GetDirectories();

    foreach (DirectoryInfo folder in directories)
       if (folder.Name.ToString().Trim() != "SubFolderA")
          {...}

A C# newbie here. Above is the code I am using to exclude "SubFolderA" which resides in my root folder (myRootFolderPath). I need to exclude all the sub-folders listed in excludeSubFolders variable.

Thank you

UPDATE: string excludeSubFolders is being populated through a parameter outside of c# code. I just listed the output of that parameter in the format c# is expecting. Also the parameter will have "SubFolderA, SubFolderB, SubFolderC, SubFolderABC" value today while the day after tomorrow, someone will change that to "SubFolderA, SubFolderB, SubFolderC" and call the same c# code. How will this work with the presented string array suggestions?

Answer 1

1. Change excludeSubFolders to be string[] array:

   string[] excludeSubFolders = new [] { "SubFolderA", "SubFolderB", "SubFolderC", "SubFolderABC" };
   

2. Use Contains method:

   foreach (DirectoryInfo folder in directories)
      if (!excludeSubFolders.Contains(folder.Name))
         {...}
   

3. To get string[] from single string use String.Split() method:

   var subFolders = input.Split(',').Select(x => x.Trim()).ToArray();
   

Answer 2

First thing I'd do is change your excludeSubFolders to a string array, because that makes it much easier to work with:

string[] excludeSubFolders = new string[] { "SubFolderA", "SubFolderB", "SubFolderC", "SubFolderABC" };

then you can use LINQ to filter out the directories that match your exclusion array:

foreach (DirectoryInfo folder in directories.Where(dir => !excludeSubFolders.Contains(dir.Name.ToString().Trim())))
{
    // ...
}

UPDATE: regarding the update to your question: if you are being handed a comma-delimited string and cannot use a string array, then you can split the string into a string array programatically:

string excludeSubFolders = "SubFolderA, SubFolderB, SubFolderC, SubFolderABC";
string[] excludeSubArray = excludeSubFolders.Split(new []{", "}, StringSplitOptions.RemoveEmptyEntries);

foreach (DirectoryInfo folder in directories.Where(dir => !excludeSubArray.Contains(dir.Name.ToString().Trim())))
{
    // ...
}