c#

Simple try the below..

System.IO.File.WriteAllBytes("Sample.pdf", bytes);

Thanks,
Pandian

You can use this
File.WriteAllBytes(@"C:\testpdf.pdf", byteArray);

Dont forget to add reference /name space  System.IO



If you are using asp.net

then  you can also try this to ask user to download instead of writing to a specific folder
private void ShowDocument(string fileName, byte[] fileContent)
  {
  //Split the string by character . to get file extension type
  string[] stringParts = fileName.Split(new char[] { '.' });
  string strType = stringParts[1];
  Response.Clear();
  Response.ClearContent();
  Response.ClearHeaders();
  Response.AddHeader("content-disposition", "attachment; filename=" + fileName);
  //Set the content type as file extension type
  Response.ContentType = strType;
  //Write the file content
  this.Response.BinaryWrite(fileContent);
  this.Response.End();
 
  }


Check my article for more http://www.c-sharpcorner.com/UploadFile/1a81c5/convert-file-to-byte-array-and-byte-array-to-files/