How to edit a column in SfDataGrid?

public partial class ViewController : UIViewController

{

   public ViewController()

   {

   }

   SfDataGrid grid = new SfDataGrid();

   ViewModel viewmodel = new ViewModel();               

   public override void ViewDidLoad()

   {

      base.ViewDidLoad();

      this.View.BackgroundColor = UIColor.White;

      grid.ItemsSource = viewmodel.Info;

      //Creation of a template column

      var textcolumn1 = new GridTextColumn

      {

         MappingName = "Name",

         UserCellType = typeof(CustomCell), //Adding a custom cell into the template column

         HeaderText = "Name"

      };

      grid.Columns.Add(textcolumn1);

      View.AddSubview(grid);

    }

   public override void ViewDidLayoutSubviews()

   {

      this.grid.Frame = new CGRect(0, 20, View.Frame.Width, View.Frame.Height - 20);

      base.ViewDidLayoutSubviews();

   }

}

public class CustomCell:GridCell

{

   private UITextField edit;

   public CustomCell ()

   {

      edit = new UITextField ();

      edit.AllowsEditingTextAttributes = true;

      edit.EditingChanged += Edit_EditingChanged;

      this.edit.ShouldReturn += (textField) =>

      {

         edit.ResignFirstResponder();

         return true;

      };

      this.AddSubview(edit);

   }

   public override void WillMoveToWindow(UIWindow window)

   {

                List<UIGestureRecognizer> gesturelist;

                if (this.GestureRecognizers != null)

                {

                                gesturelist = new List<UIGestureRecognizer>();

                                foreach (var gesture in this.GestureRecognizers)

                                                gesturelist.Add(gesture);

                                gesturelist.FirstOrDefault(ges=> ges is UITapGestureRecognizer).ShouldRecognizeSimultaneously = (gestureRecognizer, otherGestureRecognizer) => true;

                }

                base.WillMoveToWindow(window);

   }

   public void Edit_EditingChanged (object sender, EventArgs e)

   {

      var edited = this.DataColumn.Renderer.DataGrid.View.GetItemProperties ();

      edited.SetValue (this.DataColumn.RowData,

                                  edit.Text,

                                  this.DataColumn.GridColumn.MappingName );

   }

   public override void LayoutSubviews ()

   {

      edit.Frame = new CGRect(0,0,this.Frame.Width,this.Frame.Height);               

      edit.Text = Convert.ToString(DataColumn.CellValue);

      base.LayoutSubviews ();

   }

   protected override void UnLoad()

   {

      this.RemoveFromSuperview();

   }

}