detete the record from list view and in database in xamarin.android

i want to delete record from list view. so i m using long click. on long click a dialog must appear if user enters yes then delete the record.. if user press no button then dismiss..the deleterecord method is executing but no action taking place.

public class ListActivity : Activity
    {
        ListView listItems;

        protected override void OnCreate (Bundle SaveInstace)
        {
            base.OnCreate (SaveInstace);

            SetContentView (Resource.Layout.Listviewlayout);

            //back button
            ActionBar.SetDisplayHomeAsUpEnabled (true);
            //Gets ListView object instance
            Database sqldb1 = ((GlobalClass)this.Application).sqldb;

            listItems = FindViewById<ListView> (Resource.Id.listView1);

            GetCursorView ();
            //Add ItemClick event handler to ListView instance
            listItems.ItemClick += new EventHandler<AdapterView.ItemClickEventArgs> (item_Clicked);

            listItems.ItemLongClick+= new EventHandler<AdapterView.ItemLongClickEventArgs> (item_longclicked);

            }

my item_clicked method is here..


public void item_longclicked(object sender,AdapterView.ItemLongClickEventArgs e)
        {
Database sqldb1 = ((GlobalClass)this.Application).sqldb;
            TextView shName = e.View.FindViewById<TextView> (Resource.Id.Name_row);
TextView shLastName = e.View.FindViewById<TextView> (Resource.Id.LastName_row);
            TextView shAge = e.View.FindViewById<TextView> (Resource.Id.Age_row);
            int s=e.Position;
AlertDialog.Builder alert = new AlertDialog.Builder (this);
            alert.SetTitle ("Do you want to delete");
            alert.SetPositiveButton ("yes", (EventHandler<DialogClickEventArgs>)null);
            alert.SetNegativeButton ("No", (EventHandler<DialogClickEventArgs>)null);
            var dial = alert.Create ();
            dial.Show ();

            //get the buttons
            var yesbtn= dial.GetButton((int)DialogButtonType.Positive);
            var nobtn = dial.GetButton ((int)DialogButtonType.Negative);
            yesbtn.Click+=delegate 
            {
                sqldb1.DeleteRecord(s);
                GetCursorView();
            };
        }