//圓角頭像 _avatarView = new UIImageView(new RectangleF(_blockSpace, _blockSpace, 2 * _avatarRadius, 2 * _avatarRadius));UIImage img = UIImage.FromFile("profile-pic.jpg");_avatarView.Layer.Contents = img.CGImage;_avatarView.Layer.MasksToBounds = true;//如果沒有將MasksToBounds設置為true，圖片圓角無效_avatarView.Layer.CornerRadius = _avatarRadius; _avatarView.UserInteractionEnabled = true;//用戶互動屬性()_avatarView.AddGestureRecognizer(new UITapGestureRecognizer(onClickImage));

 void onClickImage() {            try            {                //UIActionSheet是在iOS彈出的選擇按鈕項的對話框，可以添加多項，并為每項添加點擊事件。                //ChangePictureActionSheetDelegate：通過重寫UIActionSheetDelegate的Clicked方法，獲取當前點擊項                UIActionSheet _actionSheet = new UIActionSheet("選擇圖片",                new ChangePictureActionSheetDelegate(this,_avatarView), "取消",                null, "從相片庫", "拍照");                                _actionSheet.ShowInView(this.View);            }            catch (Exception e)            {                Console.WriteLine("Error:" + e.Message);            } }

class ChangePictureActionSheetDelegate : UIActionSheetDelegate    {        UIViewController _controller;        UIImageView _img;        UIImagePickerController picker;        public ChangePictureActionSheetDelegate(UIViewController controller,UIImageView img)        {            _controller = controller;            _img = img;        }        public override void Clicked(UIActionSheet actionSheet, int buttonIndex)        {            Console.WriteLine("你選擇了：" + buttonIndex);            switch (buttonIndex)            {                case 1: CallPhoto(UIImagePickerControllerSourceType.Camera); break;                case 0: CallPhoto(UIImagePickerControllerSourceType.PhotoLibrary); break;                default: break;            }        }                        private void CallPhoto(UIImagePickerControllerSourceType type)        {            Console.WriteLine("Begin...");            if (UIImagePickerController.IsSourceTypeAvailable(type))            {                try                {                    picker = new UIImagePickerController();                    picker.SourceType = type;                    //允許編輯圖片                    picker.AllowsEditing = true;                    if (_controller.PresentedViewController == null)                    {                        _controller.PresentModalViewController(picker, false);                    }                    //picker.FinishedPickingImage += picker_FinishedPickingImage;(無效)                    //AvatarPickerDelegate：通過重寫UIImagePickerControllerDelegate的FinishedPickingImage方法獲取選擇的圖片                    picker.Delegate =new AvatarPickerDelegate(_img);                    Console.WriteLine("Finished");                }                catch (Exception e)                {                    Console.WriteLine("Error:" + e.Message);                }            }            else            {                Console.WriteLine("該設備不支持此操作");            }        }    }

class AvatarPickerDelegate:UIImagePickerControllerDelegate {        UIImageView _avatar;        public AvatarPickerDelegate(UIImageView _imgView) {            _avatar = _imgView;        }                public override void FinishedPickingImage(UIImagePickerController picker, UIImage image, NSDictionary editingInfo)        {            Console.WriteLine("選擇了圖片");            if (image == null)            {                Console.WriteLine("Null");            }           //更新顯示圖片            _avatar.Layer.Contents = image.CGImage;            //關閉UIImagePicker            picker.DismissModalViewControllerAnimated(true);            Console.WriteLine("完成選擇");                    }    }