C# UITableView.ScrollToRow方法代码示例

        private void OnChange(UITableView table, NSIndexPath ip)
        {
            var cell = table.CellAt (ip) as Cell;
            var size = cell.TextView.Bounds.Size;
            var newSize = cell.TextView.SizeThatFits (new CGSize (size.Width, nfloat.MaxValue));

            if (size.Height != newSize.Height) {
                UIView.AnimationsEnabled = false;
                table.BeginUpdates ();
                table.EndUpdates ();
                UIView.AnimationsEnabled = true;

                table.ScrollToRow (ip, UITableViewScrollPosition.Top, false);
            }
            Items [ip.Row] = cell.TextView.Text;
        }

        public override UITableViewCell GetCell(UITableView tableView, NSIndexPath indexPath)
        {
            var cell = tableView.CellAt (indexPath) as Cell ?? Cell.Create ();
            cell.TextView.Text = Items [indexPath.Row];

            cell.TextView.Changed += (sender, e) => {
                OnChange (tableView, indexPath);
            };

            cell.TextView.Started += (sender, e) => {
                tableView.ScrollToRow (indexPath, UITableViewScrollPosition.Top, true);
            };

            cell.NeedsUpdateConstraints ();
            cell.UpdateConstraintsIfNeeded ();
            return cell;
        }

		public override UITableViewCell GetCell (UITableView tv)
		{
			if (cell == null) {
                cell = new UITableViewCell (UITableViewCellStyle.Default, cellkey);
				cell.SelectionStyle = UITableViewCellSelectionStyle.None;

			} 
			cell.TextLabel.Text = Caption;

			var offset = (UIDevice.CurrentDevice.UserInterfaceIdiom == UIUserInterfaceIdiom.Phone) ? 20 : 90;
			cell.Frame = new CGRect(cell.Frame.X, cell.Frame.Y, tv.Frame.Width-offset, cell.Frame.Height);
			CGSize size = ComputeEntryPosition (tv, cell);
			var yOffset = (cell.ContentView.Bounds.Height - size.Height) / 2 - 1;
			var width = cell.ContentView.Bounds.Width - size.Width;
			if (textalignment == UITextAlignment.Right) {
				// Add padding if right aligned
				width -= 10;
			}
            var entryFrame = new CGRect (size.Width, yOffset + 2f, width, size.Height);

			if (entry == null) {
				entry = CreateTextField (entryFrame);
                entry.ValueChanged += (sender, e) => Value = entry.Text;
                entry.EditingChanged += (sender, e) => Value = entry.Text;
                entry.Ended += (sender, e) => Value = entry.Text;
                entry.AllEditingEvents += (sender, e) => Value = entry.Text;
				entry.ShouldReturn += delegate {

					if (ShouldReturn != null)
						return ShouldReturn ();

                    RootElement root = GetRootElement();
					EntryElement focus = null;

					if (root == null)
						return true;

					foreach (var s in root) {
						foreach (var e in s) {
							if (e == this) {
								focus = this;
							} else if (focus != null && e is EntryElement) {
								focus = e as EntryElement;
								break;
							}
						}

						if (focus != null && focus != this)
							break;
					}

					if (focus != this)
						focus.BecomeFirstResponder (true);
					else 
						focus.ResignFirstResponder (true);

					return true;
				};
				entry.Started += delegate {
					EntryElement self = null;

					if (!returnKeyType.HasValue) {
						var returnType = UIReturnKeyType.Default;

                        foreach (var e in Section) {
							if (e == this)
								self = this;
							else if (self != null && e is EntryElement)
								returnType = UIReturnKeyType.Next;
						}
						entry.ReturnKeyType = returnType;
					} else
						entry.ReturnKeyType = returnKeyType.Value;

					tv.ScrollToRow (IndexPath, UITableViewScrollPosition.Middle, true);
				};
				cell.ContentView.AddSubview (entry);
			} else
				entry.Frame = entryFrame;

			if (becomeResponder){
				entry.BecomeFirstResponder ();
				becomeResponder = false;
			}
			entry.KeyboardType = KeyboardType;

			entry.AutocapitalizationType = AutocapitalizationType;
			entry.AutocorrectionType = AutocorrectionType;
			cell.TextLabel.Text = Caption;
            cell.TextLabel.Font = TitleFont;
            cell.TextLabel.TextColor = TitleColor;

			return cell;
		}

            public void SetSelectedRow( UITableView tableView, int row )
            {
                if ( row != SelectedIndex )
                {
                    tableView.BeginUpdates( );

                    // setup a list with the rows that need to be redrawn
                    List<NSIndexPath> rowIndices = new List<NSIndexPath>();

                    // if there was previously a row selected, add it to our list
                    // so it'll be deselected
                    if ( SelectedIndex > -1 )
                    {
                        rowIndices.Add( NSIndexPath.FromRowSection( SelectedIndex, 0 ) );
                    }


                    // setup the newly selected index
                    SelectedIndex = row;
                    NSIndexPath activeIndex = NSIndexPath.FromRowSection( SelectedIndex, 0 );
                    rowIndices.Add( activeIndex );

                    // force a redraw on the row(s) so their selection state is updated
                    tableView.ReloadRows( rowIndices.ToArray( ), UITableViewRowAnimation.Fade );

                    tableView.EndUpdates( );


                    // make sure the newly selected row comes fully into view
                    tableView.ScrollToRow( activeIndex, UITableViewScrollPosition.Top, true );
                }
            }

		public override UITableViewCell GetCell (UITableView tv)
		{
			var cell = tv.DequeueReusableCell (CellKey);
			if (cell == null) {
				cell = new UITableViewCell (UITableViewCellStyle.Default, CellKey);
				cell.SelectionStyle = UITableViewCellSelectionStyle.None;
			} else 
				RemoveTag (cell, 1);
			
			if (entry == null) {
				SizeF size = ComputeEntryPosition (tv, cell);
				float yOffset = (cell.ContentView.Bounds.Height - size.Height) / 2 - 1;
				float width = cell.ContentView.Bounds.Width - size.Width;
				
				entry = CreateTextField (new RectangleF (size.Width + 30, yOffset, width - 40, size.Height + (height - 44)));
				entry.Font = inputFont;
				
				entry.Changed += delegate {
					FetchValue ();
				};
				entry.Ended += delegate {
					FetchValue ();
				};
				/*entry.ShouldReturn += delegate {
					
					if (ShouldReturn != null)
						return ShouldReturn ();
					
					RootElement root = GetImmediateRootElement ();
					EntryElement focus = null;
					
					if (root == null)
						return true;
					
					foreach (var s in root.Sections) {
						foreach (var e in s.Elements) {
							if (e == this) {
								focus = this;
							} else if (focus != null && e is EntryElement) {
								focus = e as EntryElement;
								break;
							}
						}
						
						if (focus != null && focus != this)
							break;
					}
					
					if (focus != this)
						focus.BecomeFirstResponder (true);
					else 
						focus.ResignFirstResponder (true);
					
					return true;
				};*/
				entry.Started += delegate {
					entry.ReturnKeyType = UIReturnKeyType.Default;

					tv.ScrollToRow (IndexPath, UITableViewScrollPosition.Middle, true);
				};
			}
			if (becomeResponder) {
				entry.BecomeFirstResponder ();
				becomeResponder = false;
			}
			entry.KeyboardType = KeyboardType;
			entry.AutocapitalizationType = AutocapitalizationType;
			entry.AutocorrectionType = AutocorrectionType;
			
			cell.TextLabel.Text = Caption;
            cell.TextLabel.Font = UIFont.BoldSystemFontOfSize(17);
            if (this.IsMandatory)
                cell.TextLabel.Text += "*";
			cell.ContentView.AddSubview (entry);
			return cell;
		}

        public override UITableViewCell GetCell(UITableView tv)
        {
            var cell = tv.DequeueReusableCell (CellKey);
            if (cell == null) {
                cell = new UITableViewCell (UITableViewCellStyle.Default, CellKey);
                cell.SelectionStyle = UITableViewCellSelectionStyle.None;
            } else
                RemoveTag (cell, 1);

            if (entry == null) {
                SizeF size = ComputeEntryPosition (tv, cell);
                float yOffset = (cell.ContentView.Bounds.Height - size.Height) / 4 - 1;
                float width = cell.ContentView.Bounds.Width - size.Width;

                entry = CreateTextField (new RectangleF (size.Width, yOffset, width, size.Height + (height - 11)));
                entry.Font = inputFont;

                entry.Changed += delegate {
                    FetchValue ();
                };
                entry.Ended += delegate {
                    FetchValue ();
                };
                entry.Started += delegate {
                    entry.ReturnKeyType = UIReturnKeyType.Default;

                    tv.ScrollToRow (IndexPath, UITableViewScrollPosition.Middle, true);
                };
            }
            if (becomeResponder) {
                entry.BecomeFirstResponder ();
                becomeResponder = false;
            }
            entry.KeyboardType = KeyboardType;

            entry.AutocapitalizationType = AutocapitalizationType;
            entry.AutocorrectionType = AutocorrectionType;

            cell.TextLabel.Text = Caption;
            cell.ContentView.AddSubview (entry);
            return cell;
        }

		/// <summary>
		/// Shows or hides the nullable picker
		/// </summary>
		/// <param name="dvc"></param>
		/// <param name="tableView"></param>
		/// <param name="path"></param>
		/// <returns></returns>
		private void TogglePicker(DialogViewController dvc, UITableView tableView, NSIndexPath path)
		{
			var sectionAndIndex = GetMySectionAndIndex(dvc);
			if (sectionAndIndex.Key != null)
			{
				Section section = sectionAndIndex.Key;
				int index = sectionAndIndex.Value;

				var cell = tableView.CellAt(path);

				if (_picker_present)
				{
					// Remove the picker.
					cell.DetailTextLabel.TextColor = UIColor.Gray;
					section.Remove(_inline_date_element);
					_picker_present = false;
					if (PickerClosed != null)
						PickerClosed();
				}
				else
				{
					// Show the picker.
					cell.DetailTextLabel.TextColor = UIColor.Red;
					_inline_date_element = new InlineDateElement(DateValue);

					_inline_date_element.DateSelected += (DateTime? date) =>
					{
						this.DateValue = date;
						cell.DetailTextLabel.Text = FormatDate(date);
						Value = cell.DetailTextLabel.Text;
						cell.BackgroundColor = UIColor.FromRGB(1f, 1f, 0.8f);
						if (DateSelected != null)       // Fire our changed event.
							DateSelected();
					};

					_inline_date_element.ClearPressed += () =>
					{
						DateTime? null_date = null;
						DateValue = null_date;
						cell.DetailTextLabel.Text = " ";
						Value = cell.DetailTextLabel.Text;
						cell.DetailTextLabel.TextColor = UIColor.Gray;
						section.Remove(_inline_date_element);
						_picker_present = false;
						if (PickerClosed != null)
							PickerClosed();
						cell.BackgroundColor = _defaultColor ?? UIColor.White;
					};

					section.Insert(index + 1, UITableViewRowAnimation.Bottom, _inline_date_element);
					_picker_present = true;
					tableView.ScrollToRow(_inline_date_element.IndexPath, UITableViewScrollPosition.None, true);

					if (PickerOpened != null)
						PickerOpened();
				}
			}
		}

		protected virtual void PrepareEntry(UITableView tableview){
			SizeF size = _computeEntryPosition(tableview);
			
			_entry = new UITextField (new RectangleF (size.Width+10, (ContentView.Bounds.Height-size.Height)/2-1, 320-size.Width, size.Height));
			
			TextLabel.BackgroundColor = UIColor.Clear;
			_entry.AutoresizingMask = UIViewAutoresizing.FlexibleWidth |
				UIViewAutoresizing.FlexibleLeftMargin;
			
			_entry.ValueChanged += delegate {
				if (_element != null)
					_element.Value = _entry.Text;
			};
			_entry.Ended += delegate {
				if (_element != null)
					_element.Value = _entry.Text;
			};
			
			_entry.AddTarget((object o, EventArgs r)=>{
				if (_element != null)
					_element.Value = _entry.Text;
				}, UIControlEvent.EditingChanged);
				
			_entry.ShouldReturn += delegate {
				Element elementToFocusOn = null;
				
				foreach (var c in ((Section)_element.Parent).Elements){
					if (c == _element)
						elementToFocusOn = c;
					else if (elementToFocusOn != null && c is EntryElement)
						elementToFocusOn = c as EntryElement;
				}
				if (elementToFocusOn != _element && elementToFocusOn!=null) {
                    var index = elementToFocusOn.GetIndexPath();
					var cell = tableview.CellAt(index);
                    tableview.ScrollToRow(index, UITableViewScrollPosition.Bottom, true);
					cell.BecomeFirstResponder();
				}
				else 
					_entry.ResignFirstResponder();

                if (_entry.ReturnKeyType == UIReturnKeyType.Go) {
                    _element.FireGo(this, EventArgs.Empty);
                }

				return true;
			};
			_entry.Started += delegate {
				EntryElement self = null;
				var returnType = _element.ReturnKeyType;

                if (returnType != UIReturnKeyType.Default) {
                    foreach (var e in (_element.Parent as Section).Elements){
                        if (e == _element)
                            self = _element;
                        else if (self != null && e is EntryElement)
                            returnType = UIReturnKeyType.Next;
                    }
                }
                _entry.ReturnKeyType = returnType;
			};
				
			ContentView.AddSubview (_entry);
		}

        public override UITableViewCell GetCell(UITableView tv)
        {
            var cell = tv.DequeueReusableCell (CellKey);
            if (cell == null){
                cell = new UITableViewCell (UITableViewCellStyle.Default, CellKey);
                cell.SelectionStyle = UITableViewCellSelectionStyle.None;
            } else
                RemoveTag (cell, 1);

            if (entry == null){
                SizeF size = ComputeEntryPosition (tv, cell);
                float yOffset = (GetHeight(this.GetContainerTableView(), IndexPath) - size.Height) / 2;
                float width = cell.ContentView.Bounds.Width - size.Width - 2;  // remove two pixels to fix up appearance in case this is the only control in section

                entry = CreateTextView (new RectangleF (size.Width, yOffset, width, size.Height));
                if (AcceptReturns == false)
                    entry.ReturnKeyType = UIReturnKeyType.Done;
                else
                    entry.ReturnKeyType = UIReturnKeyType.Default;

                entry.KeyboardType = UIKeyboardType.Default;
                entry.AutocorrectionType = UITextAutocorrectionType.Default;

                entry.Changed += delegate {
                    FetchValue ();
                    if (Changed != null)
                        Changed(this, new EventArgs());
                };
                entry.Ended += delegate {
                    FetchValue ();
                    if (Changed != null)
                        Changed(this, new EventArgs());
               					entry.ResignFirstResponder();
                    this.GetImmediateRootElement().TableView.EndEditing(true);
                };

                entry.Started += delegate {
                    tv.ScrollToRow (IndexPath, UITableViewScrollPosition.Middle, true);
                };
            }

            cell.TextLabel.Text = Caption;
            cell.ContentView.AddSubview (entry);
            return cell;
        }

		public override UITableViewCell GetCell(UITableView tv)
		{
			var cell = tv.DequeueReusableCell(CellKey);
			if (cell == null)
			{
				cell = new UITableViewCell(UITableViewCellStyle.Default, CellKey);
				cell.SelectionStyle = UITableViewCellSelectionStyle.None;
			}
			else
				RemoveTag(cell, 1);

			if (entry == null)
			{
				SizeF size = ComputeEntryPosition(tv, cell);
				float yOffset = (cell.ContentView.Bounds.Height - size.Height) / 2 - 1;
				float width = cell.ContentView.Bounds.Width - size.Width;
				if (textalignment == UITextAlignment.Right)
				{
					// Add padding if right aligned
					width -= 10;
				}

				entry = CreateTextField(new RectangleF(size.Width, yOffset, width, size.Height));

				entry.ValueChanged += delegate
				{
					FetchValue();
				};
				entry.Ended += delegate
				{
					FetchValue();
					if (EntryEnded != null)
					{
						EntryEnded(this, null);
					}
				};
				entry.ShouldReturn += delegate
				{

					if (ShouldReturn != null)
						return ShouldReturn();

					RootElement root = GetImmediateRootElement();
					EntryElement focus = null;

					if (root == null)
						return true;

					foreach (var s in root.Sections)
					{
						foreach (var e in s.Elements)
						{
							if (e == this)
							{
								focus = this;
							}
							else if (focus != null && e is EntryElement)
							{
								focus = e as EntryElement;
								break;
							}
						}

						if (focus != null && focus != this)
							break;
					}

					if (focus != this)
						focus.BecomeFirstResponder(true);
					else
						focus.ResignFirstResponder(true);

					return true;
				};
				entry.Started += delegate
				{
					EntryElement self = null;

					if (EntryStarted != null)
					{
						EntryStarted(this, null);
					}

					if (!returnKeyType.HasValue)
					{
						var returnType = UIReturnKeyType.Default;

						foreach (var e in (Parent as Section).Elements)
						{
							if (e == this)
								self = this;
							else if (self != null && e is EntryElement)
								returnType = UIReturnKeyType.Next;
						}
						entry.ReturnKeyType = returnType;
					}
					else
						entry.ReturnKeyType = returnKeyType.Value;

					tv.ScrollToRow(IndexPath, UITableViewScrollPosition.Middle, true);
//.........这里部分代码省略.........