WPF 實現 DataGrid/ListView 分頁控件

在WPF中，一般會選用DataGrid/ListView進行數據展現，若是數據量很少，能夠直接一個頁面顯示出來。若是數據量很大，2000條數據，一次性顯示在一個頁面中，不只消耗資源，並且用戶體驗也很糟糕。這篇博客將介紹如何建立一個分頁控件。

爲了簡單起見，這個分頁控件目前只有 首頁/上一頁/下一頁/末頁/總頁數/第幾頁 等功能。實現思路，首頁/上一頁/下一頁/末頁 這四個經過路由事件來實現，在使用時能夠使用命令進行綁定，或者直接使用都可。總頁數和第幾頁經過依賴屬性來實現，使用時將頁數進行綁定顯示便可。示例代碼以下：

Pager控件：

    <UserControl.Resources>
        <Style TargetType="{x:Type Button}">
            <Setter Property="Width" Value="22"/>
            <Setter Property="Height" Value="22"/>
        </Style>
    </UserControl.Resources>
    <Grid>
        <StackPanel Orientation="Horizontal">
            <Button x:Name="FirstPageButton" Margin="5,0" Click="FirstPageButton_Click">
                <Path Width="7" Height="10" Data="M0,0L0,10 M0,5L6,2 6,8 0,5" Stroke="Black" StrokeThickness="1" Fill="Black" VerticalAlignment="Center" HorizontalAlignment="Center" />
            </Button>
            <Button x:Name="PreviousPageButton" Margin="0,0,5,0" Click="PreviousPageButton_Click">
                <Path Width="8" Height="8" Data="M0,4L8,0 8,8z" Stroke="Black" Fill="Black" VerticalAlignment="Center" HorizontalAlignment="Center" />
            </Button>
            <TextBlock VerticalAlignment="Center">
                <Run Text="第"/>
                <Run x:Name="rCurrent" Text="0"/>
                <Run Text="頁"/>
            </TextBlock>
            <Button Margin="5,0" x:Name="NextPageButton" Click="NextPageButton_Click">
                <Path Width="8" Height="8" Data="M0,4L8,0 8,8z" Stroke="Black" Fill="Black" VerticalAlignment="Center" HorizontalAlignment="Center">
                    <Path.RenderTransform>
                        <RotateTransform Angle="180" CenterX="4" CenterY="4" />
                    </Path.RenderTransform>
                </Path>
            </Button>
            <Button Margin="0,0,5,0" x:Name="LastPageButton" Click="LastPageButton_Click">
                <Path x:Name="MainPath" Width="7" Height="10" Data="M0,0L0,10 M0,5 L6,2 6,8 0,5" Stroke="Black" StrokeThickness="1" Fill="Black" VerticalAlignment="Center" HorizontalAlignment="Center">
                    <Path.RenderTransform>
                        <RotateTransform Angle="180" CenterX="3" CenterY="5" />
                    </Path.RenderTransform>
                </Path>
            </Button>
            <TextBlock VerticalAlignment="Center">
                <Run Text="共"/>
                <Run x:Name="rTotal" Text="0"/>
                <Run Text="頁"/>
            </TextBlock>
        </StackPanel>     
    </Grid>

C#:

    public partial class Pager : UserControl
    {
        public static RoutedEvent FirstPageEvent;
        public static RoutedEvent PreviousPageEvent;
        public static RoutedEvent NextPageEvent;
        public static RoutedEvent LastPageEvent;

        public static readonly DependencyProperty CurrentPageProperty;
        public static readonly DependencyProperty TotalPageProperty;

        public string CurrentPage
        {
            get { return (string)GetValue(CurrentPageProperty); }
            set { SetValue(CurrentPageProperty, value); }
        }

        public string TotalPage
        {
            get { return (string)GetValue(TotalPageProperty); }
            set { SetValue(TotalPageProperty, value); }
        }

        public Pager()
        {
            InitializeComponent();
        }

        static Pager()
        {
            FirstPageEvent = EventManager.RegisterRoutedEvent("FirstPage", RoutingStrategy.Direct, typeof(RoutedEventHandler), typeof(Pager));
            PreviousPageEvent = EventManager.RegisterRoutedEvent("PreviousPage", RoutingStrategy.Direct, typeof(RoutedEventHandler), typeof(Pager));
            NextPageEvent = EventManager.RegisterRoutedEvent("NextPage", RoutingStrategy.Direct, typeof(RoutedEventHandler), typeof(Pager));
            LastPageEvent = EventManager.RegisterRoutedEvent("LastPage", RoutingStrategy.Direct, typeof(RoutedEventHandler), typeof(Pager));

            CurrentPageProperty = DependencyProperty.Register("CurrentPage", typeof(string), typeof(Pager), new PropertyMetadata(string.Empty,new PropertyChangedCallback(OnCurrentPageChanged)));
            TotalPageProperty = DependencyProperty.Register("TotalPage", typeof(string), typeof(Pager), new PropertyMetadata(string.Empty,new PropertyChangedCallback(OnTotalPageChanged)));
        }

        public event RoutedEventHandler FirstPage
        {
            add { AddHandler(FirstPageEvent, value); }
            remove { RemoveHandler(FirstPageEvent, value); }
        }

        public event RoutedEventHandler PreviousPage
        {
            add { AddHandler(PreviousPageEvent, value); }
            remove { RemoveHandler(PreviousPageEvent, value); }
        }

        public event RoutedEventHandler NextPage
        {
            add { AddHandler(NextPageEvent, value); }
            remove { RemoveHandler(NextPageEvent, value); }
        }

        public event RoutedEventHandler LastPage
        {
            add { AddHandler(LastPageEvent, value); }
            remove { RemoveHandler(LastPageEvent, value); }
        }

        public static void OnTotalPageChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            Pager p = d as Pager;

            if(p != null)
            {
                Run rTotal = (Run)p.FindName("rTotal");

                rTotal.Text = (string)e.NewValue;
            }
        }

        private static void OnCurrentPageChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            Pager p = d as Pager;

            if(p != null)
            {
                Run rCurrrent = (Run)p.FindName("rCurrent");

                rCurrrent.Text = (string)e.NewValue;
            }
        }

        private void FirstPageButton_Click(object sender, RoutedEventArgs e)
        {
            RaiseEvent(new RoutedEventArgs(FirstPageEvent, this));
        }

        private void PreviousPageButton_Click(object sender, RoutedEventArgs e)
        {
            RaiseEvent(new RoutedEventArgs(PreviousPageEvent, this));
        }

        private void NextPageButton_Click(object sender, RoutedEventArgs e)
        {
            RaiseEvent(new RoutedEventArgs(NextPageEvent, this));
        }

        private void LastPageButton_Click(object sender, RoutedEventArgs e)
        {
            RaiseEvent(new RoutedEventArgs(LastPageEvent, this));
        }
    }

View Code

在MainWindow中,
XAML:

    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="*"/>
            <RowDefinition Height="Auto"/>
        </Grid.RowDefinitions>

        <DataGrid Grid.Row="0" ItemsSource="{Binding FakeSource}" AutoGenerateColumns="False" CanUserAddRows="False">
            <DataGrid.Columns>
                <DataGridTextColumn Header="Item Id" Binding="{Binding Id}" Width="80"/>
                <DataGridTextColumn Header="Item Name" Binding="{Binding ItemName}" Width="180"/>
            </DataGrid.Columns>
        </DataGrid>

        <local:Pager TotalPage="{Binding TotalPage}"
                     CurrentPage="{Binding CurrentPage, Mode=TwoWay}" 
                     HorizontalAlignment="Center"
                     Grid.Row="1">
            <i:Interaction.Triggers>
                <i:EventTrigger EventName="FirstPage">
                    <i:InvokeCommandAction Command="{Binding FirstPageCommand}" />
                </i:EventTrigger>
                <i:EventTrigger EventName="PreviousPage">
                    <i:InvokeCommandAction Command="{Binding PreviousPageCommand}"/>
                </i:EventTrigger>
                <i:EventTrigger EventName="NextPage">
                    <i:InvokeCommandAction Command="{Binding NextPageCommand}" />
                </i:EventTrigger>
                <i:EventTrigger EventName="LastPage">
                    <i:InvokeCommandAction Command="{Binding LastPageCommand}"/>
                </i:EventTrigger>
            </i:Interaction.Triggers>
        </local:Pager>
    </Grid>

MainViewModel類：

public class MainViewModel : ViewModel
    {
        private ICommand _firstPageCommand;

        public ICommand FirstPageCommand
        {
            get
            {
                return _firstPageCommand;
            }

            set
            {
                _firstPageCommand = value;
            }
        }

        private ICommand _previousPageCommand;

        public ICommand PreviousPageCommand
        {
            get
            {
                return _previousPageCommand;
            }

            set
            {
                _previousPageCommand = value;
            }
        }

        private ICommand _nextPageCommand;

        public ICommand NextPageCommand
        {
            get
            {
                return _nextPageCommand;
            }

            set
            {
                _nextPageCommand = value;
            }
        }

        private ICommand _lastPageCommand;

        public ICommand LastPageCommand
        {
            get
            {
                return _lastPageCommand;
            }

            set
            {
                _lastPageCommand = value;
            }
        }

        private int _pageSize;

        public int PageSize
        {
            get
            {
                return _pageSize;
            }
            set
            {
                if(_pageSize != value)
                {
                    _pageSize = value;
                    OnPropertyChanged("PageSize");
                }
            }
        }

        private int _currentPage;

        public int CurrentPage
        {
            get
            {
                return _currentPage;
            }

            set
            {
                if(_currentPage != value)
                {
                    _currentPage = value;
                    OnPropertyChanged("CurrentPage");
                }
            }
        }

        private int _totalPage;

        public int TotalPage
        {
            get
            {
                return _totalPage;
            }

            set
            {
                if(_totalPage != value)
                {
                    _totalPage = value;
                    OnPropertyChanged("TotalPage");
                }
            }
        }

        private ObservableCollection<FakeDatabase> _fakeSoruce;

        public ObservableCollection<FakeDatabase> FakeSource
        {
            get
            {
                return _fakeSoruce;
            }
            set
            {
                if(_fakeSoruce != value)
                {
                    _fakeSoruce = value;
                    OnPropertyChanged("FakeSource");
                }
            }
        }

        private List<FakeDatabase> _source;

        public MainViewModel()
        {
            _currentPage = 1;

            _pageSize = 20;

            FakeDatabase fake = new FakeDatabase();

            _source = fake.GenerateFakeSource();

            _totalPage = _source.Count / _pageSize;

            _fakeSoruce = new ObservableCollection<FakeDatabase>();

            List<FakeDatabase> result = _source.Take(20).ToList();

            _fakeSoruce.Clear();

            _fakeSoruce.AddRange(result);

            _firstPageCommand = new DelegateCommand(FirstPageAction);

            _previousPageCommand = new DelegateCommand(PreviousPageAction);

            _nextPageCommand = new DelegateCommand(NextPageAction);

            _lastPageCommand = new DelegateCommand(LastPageAction);
        }

        private void FirstPageAction()
        {
            CurrentPage = 1;

            var result = _source.Take(_pageSize).ToList();

            _fakeSoruce.Clear();

            _fakeSoruce.AddRange(result);
        }

        private void PreviousPageAction()
        {
            if(CurrentPage == 1)
            {
                return;
            }

            List<FakeDatabase> result = new List<FakeDatabase>();

            if(CurrentPage == 2)
            {
                result = _source.Take(_pageSize).ToList();
            }
            else
            {
                result = _source.Skip((CurrentPage - 2) * _pageSize).Take(_pageSize).ToList();
            }

            _fakeSoruce.Clear();

            _fakeSoruce.AddRange(result);

            CurrentPage--;
        }

        private void NextPageAction()
        {
            if(CurrentPage == _totalPage)
            {
                return;
            }

            List<FakeDatabase> result = new List<FakeDatabase>();

            result = _source.Skip(CurrentPage * _pageSize).Take(_pageSize).ToList();

            _fakeSoruce.Clear();

            _fakeSoruce.AddRange(result);

            CurrentPage++;
        }

        private void LastPageAction()
        {
            CurrentPage = TotalPage;

            int skipCount = (_totalPage - 1) * _pageSize;
            int takeCount = _source.Count - skipCount;

            var result = _source.Skip(skipCount).Take(takeCount).ToList();

            _fakeSoruce.Clear();

            _fakeSoruce.AddRange(result);
        }
    }

View Code

綁定到UI的數據源只是須要顯示的數據，不會把全部數據都取出來。當選擇顯示頁數時，只須要將新的數據源附上便可。

總結：若是須要對該分頁控件進行擴展，例如，增長每頁顯示條數功能，只須要在Pager控件中增長相應的依賴屬性便可。

感謝您的閱讀，代碼點擊這裏下載。