C# StackLayout类代码示例

        /// <summary>
        /// Creates a new menu form.
        /// </summary>
        /// <param name="title">Window title.</param>
        /// <param name="itemNames">Item names.</param>
        /// <param name="actions">Actions.</param>
        public MenuForm(string title, string[] itemNames, Action[] actions)
        {
            Title = title;
            SelectedIndex = -1;

            if (itemNames == null || actions == null)
                return;
            if (itemNames.Length != actions.Length)
                return;

            var stackLayout = new StackLayout {Orientation = Orientation.Vertical, HorizontalContentAlignment = HorizontalAlignment.Stretch };

            for (int i = 0; i < itemNames.Length; i++)
            {
                var idx = i;

                var button = new Button { Text = itemNames[idx], Size = new Size(240, 60) }; 
                button.Click += (s, e) =>
                {
                    actions[idx]();
                    SelectedIndex = idx;
                    this.Close();
                };

                stackLayout.Items.Add(new StackLayoutItem(button, true));
            }

            Content = stackLayout;
            Size = new Size(-1, -1);
        }

        protected override void Init ()
        {
            var picker = new Picker () { Items = {"Leonardo", "Donatello", "Raphael", "Michaelangelo" } };
            var label = new Label () {Text = "This test is successful if the picker below spans the width of the screen. If the picker is just a sliver on the left edge of the screen, this test has failed." };

            Content = new StackLayout () { Children = {label, picker}};
        }

			public ChildPage(int pageNumber)
			{
				var layout = new StackLayout();
				var MyLabel = new Label {
					VerticalOptions = LayoutOptions.Center,
					HorizontalOptions = LayoutOptions.Center,
					FontSize = 21,
					TextColor = Color.White,
					Text = $"This is page {pageNumber}"
				};
				var TestBtn = new Button {
					Text = "Go to Page 2",
					IsEnabled = false,
					BackgroundColor = Color.White
				};

				if (pageNumber != 2)
				{
					TestBtn.IsEnabled = true;
					TestBtn.Clicked += TestBtn_Clicked;
				}

				layout.Children.Add(MyLabel);
				layout.Children.Add(TestBtn);
				Content = layout;
			}

		public ComplexListView()
		{
			Performance.Clear();

			var showPerf = new Button { Text = "Performance" };
			showPerf.Clicked += (sender, args) => {
				Performance.DumpStats();
				Performance.Clear();
			};

			Content = new StackLayout {
				Orientation = StackOrientation.Vertical,
				Children = {
					showPerf,
					new ListView {
						ItemTemplate = new DataTemplate (typeof (ComplexViewCell)),
						ItemsSource =
							new[] {
								"a", "b", "c", "a", "b", "c", "a", "b", "c", "a", "b", "c", "a", "b", "c", "a", "b", "c", "a", "b", "c", "a",
								"b", "c", "a", "b", "c", "a", "b", "c", "a", "b", "c", "a", "b", "c"
							}
					}
				}
			};
		}

		public PixelOffsetTransforms()
		{
			HorizontalContentAlignment = HorizontalAlignment.Stretch;
			Spacing = 5;

			var canvas = new TestCanvas();

			var offsetMode = new EnumDropDown<PixelOffsetMode>();
			offsetMode.SelectedValueBinding.Bind(canvas, c => c.PixelOffsetMode);

			var testDropDown = new DropDown();
			testDropDown.ItemTextBinding = Binding.Property((TestInfo t) => t.Name);
			testDropDown.SelectedValueBinding.Cast<TestInfo>().Bind(canvas, c => c.Test);
			testDropDown.DataStore = tests;
			testDropDown.SelectedIndex = 0;

			var options = new StackLayout
			{
				Orientation = Orientation.Horizontal,
				VerticalContentAlignment = VerticalAlignment.Center,
				Spacing = 5,
				Padding = new Padding(10),
				Items =
				{
					"PixelOffsetMode",
					offsetMode,
					"Test",
					testDropDown
				}
			};

			Items.Add(options);
			Items.Add(new StackLayoutItem(canvas, true));
		}

		protected override void Init ()
		{
			Label header = new Label {
				Text = "Search Bar",
				FontAttributes = FontAttributes.Bold,
				FontSize = 50,
				HorizontalOptions = LayoutOptions.Center
			};

			SearchBar searchBar = new SearchBar {
				Placeholder = "Enter anything",
				CancelButtonColor = Color.Red
			};

			Label reproSteps = new Label {
				Text =
					"Tap on the search bar and enter some text. The 'Cancel' button should appear. If the 'Cancel' button is not red, this is broken.",
				HorizontalOptions = LayoutOptions.Center
			};

			Content = new StackLayout {
				Children = {
					header,
					searchBar,
					reproSteps
				}
			};
		}

		protected override void Init ()
		{
			var rootGrid = new Grid {
				RowDefinitions = new RowDefinitionCollection
														  {
															 new RowDefinition { Height = new GridLength(1, GridUnitType.Star) },
															 new RowDefinition { Height = new GridLength(1, GridUnitType.Auto) },
														 },
			};


			_mainContent = new ContentView { Content = new ScrollView { Content = new Label { Text = Description } } };
			rootGrid.AddChild (_mainContent, 0, 0);


			var buttons = new StackLayout { Orientation = StackOrientation.Horizontal };

			var button1A = new Button { Text = "View 1A" };
			button1A.Clicked += (sender, args) => ShowView (_view1A);
			buttons.Children.Add (button1A);

			var button1B = new Button { Text = "View 1B" };
			button1B.Clicked += (sender, args) => ShowView (_view1B);
			buttons.Children.Add (button1B);

			var button2 = new Button { Text = "View 2" };
			button2.Clicked += (sender, args) => ShowView (_view2);
			buttons.Children.Add (button2);

			rootGrid.AddChild (buttons, 0, 1);


			Content = rootGrid;
		}

		protected override void Init ()
		{
			var listView = new ListView ();

			var selection = new Selection ();
			listView.SetBinding (ListView.ItemsSourceProperty, "Items");

			listView.ItemTemplate = new DataTemplate (() => {
				var cell = new SwitchCell ();
				cell.SetBinding (SwitchCell.TextProperty, "Name");
				cell.SetBinding (SwitchCell.OnProperty, "IsSelected", BindingMode.TwoWay);
				return cell;
			});

			var instructions = new Label {
				FontSize = 16,
				Text =
					"The label at the bottom should equal the number of switches which are in the 'on' position. Flip some of the switches. If the number at the bottom does not equal the number of 'on' switches, the test has failed."
			};

			var label = new Label { FontSize = 24 };
			label.SetBinding (Label.TextProperty, "SelectedCount");

			Content = new StackLayout {
				VerticalOptions = LayoutOptions.Fill,
				Children = {
					instructions,
					listView,
					label
				}
			};

			BindingContext = selection;
		}

		protected override void Init ()
		{
			Content = new StackLayout {
				VerticalOptions = LayoutOptions.Center,
				Children = {
					new Label {
#pragma warning disable 618
						XAlign = TextAlignment.Center,
#pragma warning restore 618
						Text = "Welcome to Xamarin Forms!"
					},
					new Button {
						Text = "Without Params (Works)",
						AutomationId = "btnOpenUri1",
						Command = new Command (() => Device.OpenUri (new Uri ("http://www.bing.com")))
					},
					new Button {
						Text = "With encoded Params (Breaks)",
						AutomationId = "btnOpenUri2",
						Command = new Command (() => Device.OpenUri (new Uri ("http://www.bing.com/search?q=xamarin%20bombs%20on%20this")))
					},
					new Button {
						Text = "With decoded Params (Breaks)",
						AutomationId = "btnOpenUri3",
						Command = new Command (() => Device.OpenUri (new Uri ("http://www.bing.com/search?q=xamarin bombs on this")))
					}
				}
			};
		}

		protected override void Init ()
		{
			var generatedImage = new Image { Aspect = Aspect.AspectFit };

			var btn = new Button { Text="generate" };

			btn.Clicked += (sender, e) => {
				var source =  GenerateBmp (60, 60, Color.Red);
				generatedImage.Source = source;

			};

			Content = new StackLayout {
				Children = {
						btn,
#pragma warning disable 618
                    new Label {Text = "GeneratedImage", Font=Font.BoldSystemFontOfSize(NamedSize.Medium)},
#pragma warning restore 618
                    generatedImage
                },
				Padding = new Thickness (0, 20, 0, 0),
				VerticalOptions = LayoutOptions.StartAndExpand,
				HorizontalOptions = LayoutOptions.CenterAndExpand
			};
		}

		protected override void Init()
		{
			var button = new Button
			{
				AutomationId = "crashButton",
				Text = "Start Test"
			};

			var success = new Label { Text = "Success", IsVisible = false, AutomationId = "successLabel" };

			var instructions = new Label { Text = "Click the Start Test button. " };

			Content = new StackLayout
			{
				HorizontalOptions = LayoutOptions.Fill,
				VerticalOptions = LayoutOptions.Fill,
				Children = { instructions, success, button }
			};

			button.Clicked += async (sender, args) =>
			{
				await Task.WhenAll(GenerateTasks());
				success.IsVisible = true;
			};
		}

		public PreviewEditorView(Control editor, Func<string> getCode)
		{
			Editor = editor;
			this.getCode = getCode;

			Orientation = Orientation.Vertical;
			FixedPanel = SplitterFixedPanel.None;
			RelativePosition = 0.4;

			previewPanel = new Panel();
			errorPanel = new Panel { Padding = new Padding(5), Visible = false, BackgroundColor = new Color(Colors.Red, .4f) };

			Panel1 = new StackLayout
			{
				HorizontalContentAlignment = HorizontalAlignment.Stretch,
				Items =
				{
					new StackLayoutItem(previewPanel, expand: true),
					errorPanel
				}
			};
			Panel2 = editor;

			timer = new UITimer { Interval = RefreshTime };
			timer.Elapsed += Timer_Elapsed;
		}

		public Issue2292 ()
		{
			var datePicker = new DatePicker ();
			var datePickerBtn = new Button {
				Text = "Click me to call .Focus on DatePicker"
			};

			datePickerBtn.Clicked += (sender, args) => {
				datePicker.Focus ();
			};

			var datePickerBtn2 = new Button {
				Text = "Click me to call .Unfocus on DatePicker"
			};

			datePickerBtn2.Clicked += (sender, args) => {
				datePicker.Unfocus ();
			};

			Content = new StackLayout {
				Children = {
					datePickerBtn, 
					datePickerBtn2, 
					datePicker,
				}
			};
		}

		protected override void Init ()
		{
			var instructions = new Label { FontSize = 24, Text = "The first ListView below should have a Xamarin logo visible in it. The second should have a pink image with white writing. If either image is not displayed, this test has failed." };

			ImageSource remoteSource =
				ImageSource.FromUri (new Uri ("https://xamarin.com/content/images/pages/branding/assets/xamagon.png"));
			ImageSource localSource = ImageSource.FromFile ("oasis.jpg");

			var remoteImage = new Image { Source = remoteSource, BackgroundColor = Color.Red };
			var localImage = new Image { Source = localSource, BackgroundColor = Color.Red };

			var listViewRemoteImage = new ListView {
				BackgroundColor = Color.Green,
				ItemTemplate = new DataTemplate (() => new TestCellGridImage (remoteImage)),
				ItemsSource = new List<string> { "1" }
			};

			var listViewLocalImage = new ListView {
				BackgroundColor = Color.Green,
				ItemTemplate = new DataTemplate (() => new TestCellGridImage (localImage)),
				ItemsSource = new List<string> { "1" }
			};

			Content = new StackLayout {
				Children = {
					instructions,
					listViewRemoteImage,
					listViewLocalImage
				}
			};
		}

		public StackLayoutGallery ()
		{
			Device.OnPlatform (iOS: () => {
				if (Device.Idiom == TargetIdiom.Tablet) {
					Padding = new Thickness (0, 0, 0, 60);
				}
			});

			var stack = new StackLayout { Orientation = StackOrientation.Vertical };
			Button b1 = new Button { Text = "Boring", HeightRequest = 500, MinimumHeightRequest = 50 };
			Button b2 = new Button {
				Text = "Exciting!",
				VerticalOptions = LayoutOptions.FillAndExpand,
				HorizontalOptions = LayoutOptions.CenterAndExpand
			};
			Button b3 = new Button { Text = "Amazing!", VerticalOptions = LayoutOptions.FillAndExpand };
			Button b4 = new Button { Text = "Meh", HeightRequest = 400, MinimumHeightRequest = 50 };
			b1.Clicked += (sender, e) => {
				b1.Text = "clicked1";
			};
			b2.Clicked += (sender, e) => {
				b2.Text = "clicked2";
			};
			b3.Clicked += (sender, e) => {
				b3.Text = "clicked3";
			};
			b4.Clicked += (sender, e) => {
				b4.Text = "clicked4";
			};
			stack.Children.Add (b1);
			stack.Children.Add (b2);
			stack.Children.Add (b3);
			stack.Children.Add (b4);
			Content = stack;
		}