Check out example codes for "c# retrieve files in folder". It will help you in understanding the concepts better.

Code Example 1

string[] filePaths = Directory.GetFiles(@"c:\MyDir\", "*.bmp");
// returns:
// "c:\MyDir\my-car.BMP"

Code Example 2

using System.IO;

string[] filePaths = Directory.GetFiles(@"c:\MyDir\");
// returns:
// "c:\MyDir\my-car.BMP"
// "c:\MyDir\my-house.jpg"

Code Example 3

string[] filePaths = Directory.GetFiles(@"c:\MyDir\", "*.bmp",
                                         SearchOption.AllDirectories);
// returns:
// "c:\MyDir\my-car.BMP"
// "c:\MyDir\Friends\james.BMP"

Learn ReactJs, React Native from akashmittal.com