Protected void Application_Error(Object sender, EventArgs e)
{
	Response.Write("Unexpected exception occured on (“ & Now  & “) ! 
" + Server.GetLastError().Message);
	Response.End();
}

<customErrors mode="On" /< 

if (some_contition) then
    throw new Exception("New Exception")
end if

Try
  [try statements ] 

Catch [exception [As type] ] [ When expression ]
  [catch statements ]
  [Exit Try ]

[Finally  [ finally statements ] ]

End Try