Hide certain directories and files in RadFileExplorer

This article demonstrates how to filter(hide) desired files from the RadFileExplorer control.  For example, this approach can be applied in case that you need to hide system files.
The best and the most simple way to do this is by using a CustomContentProvider. Bellow are the steps that we need to implement in order to get the provider to filter the items that we need to hide.

• First we need to inherit the base class - Telerik.Web.UI.Widgets.FileSystemContentProvider.
• Then we need to override its ResolveDirectory() method of the base class as follows :
  
  C# :
  

  public override DirectoryItem ResolveDirectory(string path)

  {

  DirectoryItem originalFolder = base.ResolveDirectory(path);

  FileItem[] originalFiles = originalFolder.Files;

  List<FileItem> filteredFiles = new List<FileItem>();

  // Filter the files

  foreach (FileItem originalFile in originalFiles)

  {

  if (!this.IsFiltered(originalFile.Name))

  {

  filteredFiles.Add(originalFile);

  }

  }

  DirectoryItem newFolder = new DirectoryItem(originalFolder.Name, originalFolder.Location, originalFolder.FullPath, originalFolder.Tag, originalFolder.Permissions, filteredFiles.ToArray(), originalFolder.Directories);

  return newFolder;

  }

  
  VB.NET :
  

  Public Overloads Overrides Function ResolveDirectory(ByVal path As String) As DirectoryItem

  Dim originalFolder As DirectoryItem = MyBase.ResolveDirectory(path)

  Dim originalFiles As FileItem() = originalFolder.Files

  Dim filteredFiles As New List(Of FileItem)()

  ' Filter the files

  For Each originalFile As FileItem In originalFiles

  If Not Me.IsFiltered(originalFile.Name) Then

  filteredFiles.Add(originalFile)

  End If

  Next

  Dim newFolder As New DirectoryItem(originalFolder.Name, originalFolder.Location, originalFolder.FullPath, originalFolder.Tag, originalFolder.Permissions, filteredFiles.ToArray(), _

  originalFolder.Directories)

  Return newFolder

  End Function

        In this function we filtered the files.

•  Then we need to exclude the directories that are system directories. This can be done in the ResolveRootDirectoryAsTree() function and we need to override it as follows : 
  
  C# :
  

  public override DirectoryItem ResolveRootDirectoryAsTree(string path)

  {

  DirectoryItem originalFolder = base.ResolveRootDirectoryAsTree(path);

  DirectoryItem[] originalDirectories = originalFolder.Directories;

  List<DirectoryItem> filteredDirectories = new List<DirectoryItem>();

  // Filter the folders

  foreach (DirectoryItem originalDir in originalDirectories)

  {

  if (!this.IsFiltered(originalDir.Name))

  {

  filteredDirectories.Add(originalDir);

  }

  }

  DirectoryItem newFolder = new DirectoryItem(originalFolder.Name, originalFolder.Location, originalFolder.FullPath, originalFolder.Tag, originalFolder.Permissions, originalFolder.Files, filteredDirectories.ToArray());

  return newFolder;

  }

  
  VB.NET :
  

  Public Overloads Overrides Function ResolveRootDirectoryAsTree(ByVal path As String) As DirectoryItem

  Dim originalFolder As DirectoryItem = MyBase.ResolveRootDirectoryAsTree(path)

  Dim originalDirectories As DirectoryItem() = originalFolder.Directories

  Dim filteredDirectories As New List(Of DirectoryItem)()

  ' Filter the folders

  For Each originalDir As DirectoryItem In originalDirectories

  If Not Me.IsFiltered(originalDir.Name) Then

  filteredDirectories.Add(originalDir)

  End If

  Next

  Dim newFolder As New DirectoryItem(originalFolder.Name, originalFolder.Location, originalFolder.FullPath, originalFolder.Tag, originalFolder.Permissions, originalFolder.Files, _

  filteredDirectories.ToArray())

  Return newFolder

  End Function

• In both of the overridden functions we used the IsFiltered() function. This function is a client function and for demonstration purposes we implement it as follows :
  
  C# :
  

  private bool IsFiltered(string name)

  {

  if (name.ToLower().EndsWith(".sys") || name.ToLower().Contains("_sys"))

  {

  return true;

  }

  // else

  return false;

  }

  
  VB.NET :

• Private Function IsFiltered(ByVal name As String) As Boolean

  If name.ToLower().EndsWith(".sys") OrElse name.ToLower().Contains("_sys") Then

  Return True

  End If

  ' else

  Return False

  End Function

After implementing all of the above steps, the RadFileExplorer control will filter all of the items(folders and files), that end with ‘.sys’ or contain “_sys” in their name. The full working example can be found attached to the thread.