How to get all files inside folder using C# easily?

You can simply use the "DirectoryInfo" class, and the ".GetFiles" method, as shown in below code

DirectoryInfo dir = new DirectoryInfo(@"E:\YourFolderName");
FileInfo[] AllTxtFiles= dir.GetFiles("*.txt"); //Getting only Text files

foreach(var fle in AllTextFiles)
{
   //read files content or do something
}

OR

You can simply use

foreach (string file in Directory.EnumerateFiles(folderPath, "*.txt"))
{
       //read content
    string contents = File.ReadAllText(file);
}

For both of the above solutions, you will have to use namespace "System.IO".

We can also try this, to get all files in directory and sub-directory

string[] getAllFiles= Directory.GetFiles("pathToDir/Dir", "*.*", SearchOption.AllDirectories)

 foreach (var file in allfiles){
     FileInfo info = new FileInfo(file);
     
 }

In the above code, "*.*" is search pattern, which means to select all files, whether it is text file or image or xml file or any other file.

Here is the console application sample to get all files in directory in C#

using System.IO; //required namespace

DirectoryInfo d = new DirectoryInfo(@"D:\FolderToSearch"); //Assuming Test is your Folder

FileInfo[] Files = d.GetFiles("*.txt"); //Getting Text files only using it's extension '.txt'
string str = "";

foreach(FileInfo file in Files )
{
  str = str + ", " + file.Name;
}

Console.WriteLine("All Files names are": +str);

This is just sample application code, without adding "class maiin" etc.