Preventing document Uploading to Document Library in SharePoint 2010

Question

Here is my scenario.

I would like to allow the only certain file types (doc,docx,pdf,ppt,pptx) into my document library. I wrote ItemAdding event receiver for document library as follows. but i am unable to prevent the uploading ? Can some one guide me..

{ checking the file type here. }

properties.Cancel = true;
//properties.Status = SPEventReceiverStatus.CancelWithError;
properties.ErrorMessage = "File extension not allowed here";
// properties.Status = SPEventReceiverStatus.CancelWithRedirectUrl;
SPUtility.TransferToErrorPage("Invalid File Type");

What i am doing wrong here... ?

Answer 1

You have to do following:

        properties.RedirectUrl = properties.Web.ServerRelativeUrl +
          "/_layouts/settings.aspx";
    properties.Status = SPEventReceiverStatus.CancelWithRedirectUrl;
properties.Cancel = true;

Or

properties.ErrorMessage = "File extension not allowed here";    
properties.Status = SPEventReceiverStatus.CancelWithError;
properties.Cancel = true;

This is new to SharePoint 2010. More information here

EDIT: You can also block files of certain types at Web Application Level (without custom code), if that works for you: http://technet.microsoft.com/en-us/library/cc262496.aspx

Answer 2

if(allowed file types checking) // your file type checking
{
    //allowed file types
}
else
{
    properties.Cancel = true;
    properties.Status = SPEventReceiverStatus.CancelWithRedirectUrl;
    properties.RedirectUrl = "/_layouts/error_Custom.aspx?Error=" + "Your error Message";
    //if you create any custom error page 
    this.EventFiringEnabled = false;
}