It seems that you have both of following using statements :
using System.Windows.Input;
using Microsoft.Phone.Controls;
which can cause conflict since there is a different GestureEventArgs
class defined in each of above namespace.
You can use namespace alias to resolve this conflict, for example, add following using statement if you meant to use GestureEventArgs
from System.Windows.Input.GestureEventArgs
namespace :
using GestureEventArgs = System.Windows.Input.GestureEventArgs;
void focus_Tapped(object sender, GestureEventArgs e)
{
.......
}
or another option is using fully-qualified class name :
void focus_Tapped(object sender, System.Windows.Input.GestureEventArgs e)
{
.......
}