In C# CSOM How to Delete Folders Recursively, Sub-Folders, Files in SharePoint Online Document Library

In this article we will see how to delete Root folder, sub-folders, files in SharePoint Document Library. 

Here I have given snippet by hardcoding (not recommended) one folder name "TestFolder1". 

However you can use loop statement and iterate list of root folder names. 

var clientContext = GetClientContextWithAccessToken(siteUrl, accessToken);
Web web = clientContext.Web;
clientContext.Load(web);
clientContext.ExecuteQuery();

//Here you can add for loop with list of root folder names and iterate

//Start of for loop
string folderPath = "/sites/contoso5/LibraryName/TestFolder1"; //Pass the folder name dynamically
Folder folder = clientContext.Web.GetFolderByServerRelativeUrl(folderPath);
clientContext.Load(folder, folderitem => folderitem.Properties, folderitem => folderitem.Name, folderitem => folderitem.Files);
clientContext.ExecuteQuery();
DeleteFolderRecursive(folder); //Call method to delete subfolders and files.
folder.DeleteObject();
clientContext.ExecuteQuery();
//End of for loop

//This method will delete all subfolders and files in the given folder
private static void DeleteFolderRecursive(Folder folder)
{
    using(ClientContext ctx = (ClientContext)folder.Context)
    {
      ctx.Load(folder);
      ctx.ExecuteQuery();
      FileCollection files = folder.Files;
      ctx.Load(files);
      ctx.ExecuteQuery();
      File[] filesArray = new File[files.Count];
      filesArray = files.ToArray();
      foreach(File file in filesArray)
      {
         file.DeleteObject();
      }

      FolderCollection subfolders = folder.Folders;
      ctx.Load(subfolders);
      ctx.ExecuteQuery();

      Folder[] subfoldersArray = new Folder[subfolders.Count];
      subfoldersArray = subfolders.ToArray();
      foreach(Folder subfolder in subfoldersArray)
      {
         DeleteFolderRecursive(subfolder);
         subfolder.DeleteObject();
      }

      ctx.Load(folder);
      ctx.ExecuteQuery();
   }
}

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