原文:
WPF MvvmLight简单实例(1) 页面导航
实现了那些功能，先看看截图：
操作描述：
在程序运行后，点击“Load”按钮，页面会加载PageOne,点击PageOne页面中的“Next”按钮即可进入PageTwo页面，
点击PageTwo页面中的“Next”即可进入PageThree页面，点击Back可返回Page1页面
第一步：新建工程并使用NuGet安装MvvmLight
第二步：添加Views文件夹并添加相应的ViewModel
本文主要描述如何使用MvvmLight实现简单的导航效果，所以页面基本上都是大同小异比较简单ViewModel也比较简单，所以这里只PageOne.xaml以及PageOneViewModel.cs
PageOne.xaml代码:
<Page x:Class="MvvmLightSample.Views.PageOne" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:local="clr-namespace:MvvmLightSample.Views" mc:Ignorable="d" Title="PageOne"> <Page.DataContext> <Binding Path="PageOne" Source="{StaticResource Locator}"></Binding> </Page.DataContext> <Grid Background="Orange"> <TextBlock Text="1" Foreground="White" FontSize="30"></TextBlock> <StackPanel Orientation="Vertical" HorizontalAlignment="Center" VerticalAlignment="Center"> <TextBlock Text="{Binding Title}" FontSize="18" Foreground="White"></TextBlock> <Button Width="80" Height="20" Content="Click me!!!" Margin="0,20,0,0" Command="{Binding ChangeCommand}"></Button> </StackPanel> <Button Command="{Binding GoToNextCommand}" Content="Next" Width="60" Height="30" VerticalAlignment="Bottom" HorizontalAlignment="Right" Margin="0,0,10,10"></Button> </Grid> </Page>
PageOneViewModel.cs代码:
public class PageOneViewModel : ViewModelBase { private INavigationService _navigationService; public ICommand GoBackCommand { get; set; } public ICommand GoToNextCommand { get; set; } public ICommand ChangeCommand { get; set;} private string _title; public string Title { get { return _title; } set { Set(()=>Title,ref _title,value); } } public PageOneViewModel(INavigationService navigationService) { _navigationService = navigationService; Title = "Please Click me!"; GoBackCommand = new RelayCommand(GoBack); GoToNextCommand = new RelayCommand(GotoNext); ChangeCommand = new RelayCommand(ChangeTitle); } private void ChangeTitle() { Title = "Hello MvvmLight!!!"; } private void GoBack() { _navigationService.GoBack(); } private void GotoNext() { var navigationService = ServiceLocator.Current.GetInstance<INavigationService>(); navigationService.NavigateTo("PageTwo2"); } }
第三步:修改ViewModelLocator.cs
public class ViewModelLocator { /// <summary> /// Initializes a new instance of the ViewModelLocator class. /// </summary> public ViewModelLocator() { ServiceLocator.SetLocatorProvider(() => SimpleIoc.Default); SimpleIoc.Default.Register<MainViewModel>(); SimpleIoc.Default.Register<PageOneViewModel>(); SimpleIoc.Default.Register<PageTwoViewModel>(); SimpleIoc.Default.Register<PageThreeViewModel>(); SimpleIoc.Default.Register<PageFourViewModel>(); var navigationService = this.CreateNavigationService(); SimpleIoc.Default.Register<INavigationService>(() => navigationService); } private INavigationService CreateNavigationService() { var nav = new NavigationService(); var navigationService = new NavigationService(); navigationService.Configure("PageTwo1", new Uri("/MvvmLightSample;component/Views/PageOne.xaml", UriKind.Relative)); navigationService.Configure("PageTwo2", new Uri("/MvvmLightSample;component/Views/PageTwo.xaml", UriKind.Relative)); navigationService.Configure("PageTwo3", new Uri("/MvvmLightSample;component/Views/PageThree.xaml", UriKind.Relative)); navigationService.Configure("PageTwo4", new Uri("/MvvmLightSample;component/Views/PageFour.xaml", UriKind.Relative)); return navigationService; } public MainViewModel Main { get { return ServiceLocator.Current.GetInstance<MainViewModel>(); } } public PageOneViewModel PageOne { get { return ServiceLocator.Current.GetInstance<PageOneViewModel>(); } } public PageTwoViewModel PageTwo { get { return ServiceLocator.Current.GetInstance<PageTwoViewModel>(); } } public PageThreeViewModel PageThree { get { return ServiceLocator.Current.GetInstance<PageThreeViewModel>(); } } public PageFourViewModel PageFour { get { return ServiceLocator.Current.GetInstance<PageFourViewModel>(); } } public static void Cleanup() { } }
NavigationService.cs代码:
public class NavigationService : ViewModelBase,INavigationService { private readonly Dictionary<string, Uri> _pagesByKey; private readonly List<string> _historic; private string _currentPageKey; #region Properties public string CurrentPageKey { get { return _currentPageKey; } private set { Set(()=>CurrentPageKey,ref _currentPageKey,value); } } public object Parameter { get; private set; } #endregion #region Ctors and Methods public NavigationService() { _pagesByKey = new Dictionary<string, Uri>(); _historic = new List<string>(); } public void GoBack() { if (_historic.Count > 1) { _historic.RemoveAt(_historic.Count - 1); NavigateTo(_historic.Last(), "Back"); } } public void NavigateTo(string pageKey) { NavigateTo(pageKey, "Next"); } public virtual void NavigateTo(string pageKey, object parameter) { lock (_pagesByKey) { if (!_pagesByKey.ContainsKey(pageKey)) { throw new ArgumentException(string.Format("No such page: {0} ", pageKey), "pageKey"); } var frame = GetDescendantFromName(Application.Current.MainWindow, "MainFrame") as Frame; if (frame != null) { frame.Source = _pagesByKey[pageKey]; } Parameter = parameter; if (parameter.ToString().Equals("Next")) { _historic.Add(pageKey); } CurrentPageKey = pageKey; } } public void Configure(string key, Uri pageType) { lock (_pagesByKey) { if (_pagesByKey.ContainsKey(key)) { _pagesByKey[key] = pageType; } else { _pagesByKey.Add(key, pageType); } } } private static FrameworkElement GetDescendantFromName(DependencyObject parent, string name) { var count = VisualTreeHelper.GetChildrenCount(parent); if (count < 1) { return null; } for (var i = 0; i < count; i++) { var frameworkElement = VisualTreeHelper.GetChild(parent, i) as FrameworkElement; if (frameworkElement != null) { if (frameworkElement.Name == name) { return frameworkElement; } frameworkElement = GetDescendantFromName(frameworkElement, name); if (frameworkElement != null) { return frameworkElement; } } } return null; } #endregion }
源码下载地址:http://download.csdn.net/detail/qindongshou1/9481969
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