C# ObservableCollection.LastOrDefault方法代码示例

        public AddVirtualEnvironmentView(
            PythonProjectNode project,
            IInterpreterRegistryService interpreterService,
            IPythonInterpreterFactory selectInterpreter
        ) {
            _interpreterService = interpreterService;
            _project = project;
            VirtualEnvBasePath = _projectHome = project.ProjectHome;
            Interpreters = new ObservableCollection<InterpreterView>(InterpreterView.GetInterpreters(project.Site, project));
            var selection = Interpreters.FirstOrDefault(v => v.Interpreter == selectInterpreter);
            if (selection == null) {
                selection = Interpreters.FirstOrDefault(v => v.Interpreter == project.GetInterpreterFactory())
                    ?? Interpreters.LastOrDefault();
            }
            BaseInterpreter = selection;

            _project.InterpreterFactoriesChanged += OnInterpretersChanged;

            var venvName = "env";
            for (int i = 1; Directory.Exists(Path.Combine(_projectHome, venvName)); ++i) {
                venvName = "env" + i.ToString();
            }
            VirtualEnvName = venvName;

            CanInstallRequirementsTxt = File.Exists(PathUtils.GetAbsoluteFilePath(_projectHome, "requirements.txt"));
            WillInstallRequirementsTxt = CanInstallRequirementsTxt;
        }

        public async Task<ObservableCollection<ForumCategoryEntity>> GetForumCategoryMainPage()
        {
            var forumGroupList = new ObservableCollection<ForumCategoryEntity>();
            var result = await _webManager.GetData(Constants.FORUM_LIST_PAGE);
            HtmlDocument doc = result.Document;

            HtmlNode forumNode =
                doc.DocumentNode.Descendants("select")
                    .FirstOrDefault(node => node.GetAttributeValue("name", string.Empty).Equals("forumid"));
            if (forumNode != null)
            {
                try
                {
                    IEnumerable<HtmlNode> forumNodes = forumNode.Descendants("option");

                    foreach (HtmlNode node in forumNodes)
                    {
                        string value = node.Attributes["value"].Value;
                        int id;
                        if (!int.TryParse(value, out id) || id <= -1) continue;
                        if (node.NextSibling.InnerText.Contains("--"))
                        {
                            string forumName =
                                WebUtility.HtmlDecode(node.NextSibling.InnerText.Replace("-", string.Empty));
                            bool isSubforum = node.NextSibling.InnerText.Count(c => c == '-') > 2;
                            var forumSubCategory = new ForumEntity
                            {
                                Name = forumName.Trim(),
                                Location = string.Format(Constants.FORUM_PAGE, value),
                                IsSubforum =  isSubforum
                            };
                            forumSubCategory.SetForumId();
                            forumGroupList.LastOrDefault().ForumList.Add(forumSubCategory);
                        }
                        else
                        {
                            string forumName = WebUtility.HtmlDecode(node.NextSibling.InnerText);
                            var forumGroup = new ForumCategoryEntity(forumName,
                                string.Format(Constants.FORUM_PAGE, value));
                            forumGroupList.Add(forumGroup);
                        }
                    }
                }
                catch (Exception ex)
                {
                    throw new Exception("Main Forum Parsing Error: " + ex.StackTrace);
                }
            }

#if DEBUG
            if (forumGroupList.Any())
                forumGroupList[3].ForumList.Add(AddDebugForum());
#endif

            return forumGroupList;
        }

		private void ParseResult(string response)
		{
			try
			{
				var collection = new ObservableCollection<Hilite>();
				var result = JObject.Parse(response);
				if (!bool.Parse(result["success"].ToString()))
				{
					Dispatcher.BeginInvoke(() => MessageBox.Show(result["errorMessage"].ToString(), AppResources.ErrorTitle, MessageBoxButton.OK));
				}
				else
				{
					if (!bool.Parse(result["isNextFetch"].ToString()))
					{
						IsolatedStorageSettings.ApplicationSettings["LastHiliteFetch"] = result["currentTimestamp"].ToString();
					}
					else
					{
						collection = HiliteCollection;
						var last = collection.LastOrDefault();
						if (last != null)
						{
							last.IsLast = false;
						}
					}
					var messages = JArray.Parse(result["messages"].ToString());
					foreach (var hilite in messages.Select(hiliteRow => JObject.Parse(hiliteRow.ToString())))
					{
						var hiliteObj = new Hilite
						                	{
						                		Channel = hilite["channel"].ToString(),
						                		Nick = hilite["nick"].ToString(),
						                		Message = hilite["message"].ToString(),
						                		TimestampString = hilite["timestamp"].ToString(),
						                		Id = long.Parse(hilite["id"].ToString())
						                	};
						collection.Add(hiliteObj);
					}
					if (result["nextMessage"].Type != JTokenType.Null)
					{
						var nextHilite = JObject.Parse(result["nextMessage"].ToString());
						_nextHilite = new Hilite
						              	{
						              		Channel = nextHilite["channel"].ToString(),
						              		Nick = nextHilite["nick"].ToString(),
						              		Message = nextHilite["message"].ToString(),
						              		TimestampString = nextHilite["timestamp"].ToString(),
						              		Id = long.Parse(nextHilite["id"].ToString())
						              	};
						var last = collection.LastOrDefault();
						if (last != null)
						{
							last.IsLast = true;
						}
					}
					else
					{
						_nextHilite = null;
						var last = collection.LastOrDefault();
						if (last != null)
						{
							last.IsLast = false;
						}
					}
					HiliteCollection = collection;
				}
			}
			catch (Exception e)
			{
				Dispatcher.BeginInvoke(() => MessageBox.Show(string.Format(AppResources.ErrorFetchingMessagesEx, e), AppResources.ErrorTitle, MessageBoxButton.OK));
			}
			IsBusy = false;
		}

        /// <summary>
        /// The get data source for update depreciation screen.
        /// </summary>
        /// <returns>
        /// The <see cref="Task"/>.
        /// </returns>
        private async Task GetDataSourceForUpdateDepreciationScreen()
        {
            if (this.DynamicMainGridViewModel.SelectedItems != null)
            {
                // Get Type name for UpdateDepreciation screen
                string updateDepreciationName = default(string);
                var allItemsSelected = new ObservableCollection<AssetClassesTypeRowItem>(this.DynamicMainGridViewModel.SelectedItems.Cast<AssetClassesTypeRowItem>());
                foreach (var item in allItemsSelected)
                {
                    var assetClassesTypeRowItem = allItemsSelected.FirstOrDefault();
                    var classesTypeRowItem = allItemsSelected.LastOrDefault();
                    if (classesTypeRowItem != null && (assetClassesTypeRowItem != null && (item.EquipTypeId == assetClassesTypeRowItem.EquipTypeId || item.EquipTypeId == classesTypeRowItem.EquipTypeId)))
                    {
                        updateDepreciationName = updateDepreciationName + item.TypeDescription;
                    }
                    else
                    {
                        updateDepreciationName = updateDepreciationName + ", " + item.TypeDescription;
                    }
                }

                await this.TypeUpdateDepreciationViewModel.GenerateUserControlForDetailScreen();
                await this.TypeUpdateDepreciationViewModel.GetUpdateDepreciationDataSource(updateDepreciationName, await AssetClassesTypeFunctions.GetDefaultDataForDetail());
                this.TypeUpdateDepreciationViewModel.ContentItemChanged = this.AssetClassesTypeDetailViewModel_PropertyChanged;
            }
        }

//.........这里部分代码省略.........

            _changeMapTypeCommand =
                new Command<MapType>(m => MapDisplayType = m);

            _addPinCommand =
                new Command(AddPin, o => _allPins.Any());

            _removePinCommand =
                new Command(RemovePin, o => Pins.Any());

            _moveToRegionCommand =
                new Command(() => Map.MoveToRegion(animated: true));

            _addPolylineCommand =
                new Command(AddPolyline, o => _allPolylines.Any());

            _removePolylineCommand =
                new Command(RemovePolyline, o => Overlays.Any());

            _selectCommand =
                new Command<int>(SetSelectedItem, (arg) => Pins.Count > 0);

            _allPins = new LinkedList<IMapPin> (
                new []
                {
                    new MapPin
                    {
                        Title = "Brändlen",
                        Location = new Position(46.904829, 8.409724),
                        Color = Color.Red
                    },
                    new MapPin
                    {
                        Title = "Wolfenschiessen",
                        Snippet = "... nothing to see here",
                        Location = new Position(46.905180, 8.398110),
                        Color = Color.Blue
                    },
                    new MapPin
                    {
                        Title = "Klewenalp",
                        Location = new Position(46.939898, 8.475217),
                        Color = Color.Fuchsia,
                    },
                    new MapPin
                    {
                        Title = "Beckenried NW",
                        Location = new Position(46.963876, 8.482078),
                        Color = Color.Green,
                    },
                    new MapPin
                    {
                        //Title = "Zürich",
                        //Snippet = "It's awesome",
                        Location = new Position(47.3667, 8.5500),
                        Image = "pin_icon",
                        SelectedImage = "pin_icon_active",
                        Anchor = new Point(0.5, 1)
                    },
                    new MapPin
                    {
                        Title = "fivenine",
                        Snippet = "fivenine GmbH",
                        Location = new Position(47.389097, 8.517756),
                        Image = "pin_icon",
                        SelectedImage = "pin_icon_active",
                        Anchor = new Point(0.5, 1)
                    },
                });

            Pins = new ObservableCollection<IMapPin> ();

            _allPolylines = new LinkedList<IMapOverlay> ();

            var polyline = new PolylineOverlay ();
            foreach (var pin in _allPins) {
                polyline.Add (pin.Location);
            }

            _allPolylines.AddLast (polyline);

            Overlays = new ObservableCollection<IMapOverlay> ();

            Overlays.Add(new CircleOverlay
            {
                Location = new Position(47.389097, 8.517756),
                Radius = 400,
                Color = Color.Navy.MultiplyAlpha(0.2),
                FillColor = Color.Blue.MultiplyAlpha(0.2)
            });

            // Add some sample pins
            AddPin (null);
            AddPin (null);

            // Add some polylines
            AddPolyline (null);

            SelectedItem = Pins.LastOrDefault();
        }

        private void setLineData(int days)
        {
            DateTime start = DateTime.Today.AddDays(-days);

            _LineData = new ObservableCollection<LData>(
                (from p in APPDB.Outgoing
                 where p.Time > start
                 group p by p.Time into g
                 select new LData
                 {
                    // time = g.Key.ToShortDateString(),
                    time="",
                     value = g.Sum(p => p.Money)/100
                 }
                 )
              );
            if (_LineData.Count != 0)
            {
                _LineData[0].time = start.ToShortDateString();
                _LineData.LastOrDefault().time = DateTime.Today.ToShortDateString();
            }
            //int count = _LineData.Count;
            //if (count < 3)
            //    return;
            //int step = count / 3;
            //int index = 0;
            //foreach (var i in _LineData)
            //{
            //    if (index % step != 0)
            //        i.time = "";
            //    index++;
            //}
        }

        /**
         *  返回_pieData,_lineData,_RecentData,homeinfo
         */
        private void initHomePage(object sender, DoWorkEventArgs e)
        {
            YingDB DB = App.APPDB;
            Home_info HomeInfo = DB.Home_info.FirstOrDefault();
            DateTime today = DateTime.Today;
            initResult result = new initResult();
            //获取首页信息
            if (HomeInfo.Date.Year == today.Year)
            {
                if (HomeInfo.Date.Month != today.Month)
                {
                    HomeInfo.Mouthsum = 0;
                    HomeInfo.Daysum = 0;
                }
                else
                {
                    if (HomeInfo.Date != today)
                        HomeInfo.Daysum = 0;
                }
            }
            else
            {
                HomeInfo.Weeksum = 0;
                HomeInfo.Daysum = 0;
            }
            HomeInfo.Date = today;
            if ((today - HomeInfo.Weekstart).Days > 7)
            {
                HomeInfo.Weeksum = 0;
                HomeInfo.Weekstart = today.AddDays(-(int)today.DayOfWeek);
            }
            result.HomeInfo = HomeInfo;

            //最近数据
            ObservableCollection<HData> recentData = new ObservableCollection<HData>(
                (
                from p in APPDB.Outgoing
                join g in APPDB.Sub_type on p.Sub_id equals g.Id
                orderby p.Id descending
                select new HData { Name=g.Name,value=p.Money}
                ).Take(7)
                );
            result.RecentData = recentData;

            //7天饼图数据
            DateTime start = DateTime.Today.AddDays(-7);
            ObservableCollection<PData> PieData = new ObservableCollection<PData>(
                (from p in APPDB.Outgoing
                 where p.Time > start
                 group p by p.Main_id into g
                 join m in APPDB.Main_type on g.Key equals m.Id
                 select new PData { title = m.Name, value = g.Sum(p => p.Money) / 100 }
                     )
                );
            result.pieData = PieData;

            //30天线图数据

            start = DateTime.Today.AddDays(-30);

            ObservableCollection<LData> LineData = new ObservableCollection<LData>(
                (from p in APPDB.Outgoing
                 where p.Time > start
                 group p by p.Time into g
                 select new LData
                 {
                     // time = g.Key.ToShortDateString(),
                     time = "",
                     value = g.Sum(p => p.Money) / 100
                 }
                 )
              );
            if (LineData.Count != 0)
            {
                LineData[0].time = start.ToShortDateString();
                LineData.LastOrDefault().time = DateTime.Today.ToShortDateString();
            }
            result.LineData = LineData;
            e.Result = result;
        }

 private void AddAbstract()
 {
     var abs = DefaultManager.Instance.DefaultAbstract;
     abs.PersonConferenceId = CurrentPersonConference.PersonConferenceId;
     DataManager.Instance.AddAbstract(abs);
     AllAbstracts = new ObservableCollection<Abstract>(DataManager.Instance.GetAbstractsByPersonConferenceID(CurrentPersonConference.PersonConferenceId));
     CurrentAbstract = AllAbstracts.LastOrDefault();
     OnPropertyChanged("CurrentAbstract");
     OnPropertyChanged("AllAbstracts");
 }