MonoTouch Add constraint to UITextField programmatically - ios6

Question

I have a UITextView added programmatically in a tableview. I would like to add constraint to it so it will look same in portrait and landscape mode. I have following code(C#, MonoTouch) but it doesnot work. titleTxt is the simple textfield added to the cell.
var rightSpaceConstraint = NSLayoutConstraint.Create (titleTxt, NSLayoutAttribute.Trailing, NSLayoutRelation.Equal, null, NSLayoutAttribute.Right, 1.0f, 20f);
var leftSpaceConstraint = NSLayoutConstraint.Create (titleTxt, NSLayoutAttribute.Leading, NSLayoutRelation.Equal, null, NSLayoutAttribute.Left, 1.0f, 20f);
titleTxt.AddConstraints (new NSLayoutConstraint[] {rightSpaceConstraint, leftSpaceConstraint});
How should i add constraint to set left and right spaces.

Answer 1

Rather than adding constraint to titleTxt you have to add the constraint to table cell. Also you have to set the TranslatesAutoresizingMaskIntoConstraints flag to false.
Below is the code that works fine
UILabel titleLbl = new UILabel ();
titleLbl.Frame = new RectangleF (20,5,260,30);
titleLbl.Text = "Please enter username";
titleLbl.BackgroundColor = UIColor.Clear;
titleLbl.Font = UIFont.SystemFontOfSize (13);
titleLbl.TextAlignment = UITextAlignment.Center;
titleLbl.AutoresizingMask = UIViewAutoresizing.FlexibleWidth;
titleLbl.TranslatesAutoresizingMaskIntoConstraints = false;
cell.ContentView.AddSubview (titleLbl);
var titleLblRightSpaceConstraint = NSLayoutConstraint.Create (titleLbl, NSLayoutAttribute.Trailing, NSLayoutRelation.Equal, cell.ContentView, NSLayoutAttribute.Right, 1.0f, -20f);
var titleLblLeftSpaceConstraint = NSLayoutConstraint.Create (titleLbl, NSLayoutAttribute.Leading, NSLayoutRelation.Equal, cell.ContentView, NSLayoutAttribute.Left, 1.0f, 0f);
cell.ContentView.AddConstraints (new NSLayoutConstraint[] {titleLblRightSpaceConstraint, titleLblLeftSpaceConstraint });