Define blocked file types in SharePoint 2010

In this article we will be seeing about blocked file types in SharePoint 2010. Each Web application maintains a list of blocked file types that is based on file name extensions which can be restricted from being uploaded or downloaded.

Using Central Administration:

• Go to Central Administration => Security => General Security => Define blocked file types.
  
  
  
• Select the web application from the drop down.
• Type the file extension that has to be added in the blocked file types.
• Click on Ok.
  
  
  

Using Visual Studio 2010:

• Open Visual Studio 2010.
• Go to File => New => Project.
• Select Console Application from the installed templates.
• Enter the Name and click Ok.
• Add the following references.
  
  o Microsoft.SharePoint.dll
  
• Add the following namespaces.
  
  o using Microsoft.SharePoint;
  o using System.Collections.ObjectModel;
  
• Replace the code with the following.
  
  string webAppUrl = "http://serverName:10/";
  string addBlockFileType = "aspx";
  string removeBlockFileType = "asp";
  SPWebApplication webApp = SPWebApplication.Lookup(new Uri(webAppUrl));
  Collection<string> blockFileTypes = webApp.BlockedFileExtensions;
  foreach (string fileExtension in blockFileTypes)
  {
  // displaying all the file extensions that are blocked
  Console.WriteLine(fileExtension.ToString());
  }
  Console.ReadLine();

  // adding blocked file type
  blockFileTypes.Add(addBlockFileType);

  // removing blocked file type
  blockFileTypes.Remove(removeBlockFileType);

  webApp.Update();
  
  

• Build the solution.

• Hit F5.

• All the file extensions from the blocked file type will be displayed as shown in the following.
  
  
  

• A new file extension "aspx" is added and the existing file extension "asp" is removed successfully.