WPF MVVM DataGird 数据分页

一、原理及效果图

 

 

二、视图Model

 public class Student
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Address { get; set; }
        public int Age { get; set; }
    }

    public class StudentDao
    {
        List<Student> listStu = new List<Student>();
        public int GetTotalCount
        {
            get
            {
                return listStu.Count;
            }
        }

        public StudentDao()
        {
            for (int i = 1; i < 100; i++)
            {
                listStu.Add(new Student() { Id = i, Age = i, Name = "YY", Address = "湖南长沙" });
            }
        }

        /// <summary>
        /// 数据分页
        /// </summary>
        /// <param name="startNum">开始的索引</param>
        /// <param name="count">数量</param>
        /// <returns></returns>
        public List<Student> GetListStu(int startNum, int count)
        {
            return listStu.Skip(startNum).Take(count).Cast<Student>().ToList();
        }
    }

三、实现命令接口

  class CommandOperation : ICommand
    {
        private Action execute;
        private Action<object> exrcuteParameter;
        public CommandOperation(Action execute)
        {
            this.execute = execute;
        }
        public CommandOperation(Action<object> execute)
        {
            this.exrcuteParameter = execute;
        }
        public bool CanExecute(object parameter)
        {
            return true;
        }

        public event EventHandler CanExecuteChanged;

        public void Execute(object parameter)
        {
            if (exrcuteParameter != null)
            {
                exrcuteParameter(parameter);
                return;
            }
            execute();
        }
    }

 四、ViewModel

public class PropertyChangedBase : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        public void NotifyPropertyChanged(string propertyName)
        {
            if (this.PropertyChanged != null)
            {
                this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }

    }

    public static class PropertyChangedBaseEx
    {
        public static void NotifyPropertyChanged<T, TProperty>(this T propertyChangedBase,
          Expression<Func<T, TProperty>> expression) where T : PropertyChangedBase
        {
            var memberExpression = expression.Body as MemberExpression;
            if (memberExpression != null)
            {
                string propertyName = memberExpression.Member.Name;
                propertyChangedBase.NotifyPropertyChanged(propertyName);
            }
            else
                throw new NotImplementedException();
        }
    }
    public class StuentViewModel : PropertyChangedBase
    {
        #region 通知属性

        private int totalCount;

        public int TotalCount
        {
            get { return totalCount; }
            set
            {
                totalCount = value;
                this.NotifyPropertyChanged(d => d.TotalCount);
            }
        }

        private int pageCount;

        public int PageCount
        {
            get { return pageCount; }
            set
            {
                pageCount = value;
                this.NotifyPropertyChanged(d => d.PageCount);
            }
        }

        private int totalPage;

        public int TotalPage
        {
            get { return totalPage; }
            set
            {
                totalPage = value;
                this.NotifyPropertyChanged(d => d.TotalPage);
            }
        }

        private int currentPage;

        public int CurrentPage
        {
            get { return currentPage; }
            set
            {
                currentPage = value;
                this.NotifyPropertyChanged(d => d.CurrentPage);
            }
        }

        private int currentStart;

        public int CurrentStart
        {
            get { return currentStart; }
            set
            {
                currentStart = value;
                this.NotifyPropertyChanged(d => d.CurrentStart);
            }
        }

        private int currentEnd;

        public int CurrentEnd
        {
            get { return currentEnd; }
            set
            {
                currentEnd = value;
                this.NotifyPropertyChanged(d => d.CurrentEnd);
            }
        }

        private List<Student> listModel;

        public List<Student> ListModel
        {
            get { return listModel; }
            set
            {
                listModel = value;
                this.NotifyPropertyChanged(d => d.ListModel);
            }
        }



        #endregion

        #region 命令属性

        public ICommand CommNext { get; private set; }
        public ICommand CommLast { get; private set; }
        public ICommand CommFirst { get; private set; }
        public ICommand CommPrev { get; private set; }
        public ICommand CommPageCount { get; private set; }
      
        #endregion

        private StudentDao stuDao = new StudentDao();
        public StuentViewModel()
        {
            CommFirst = new CommandOperation(First);
            CommPrev = new CommandOperation(Prev);
            CommNext = new CommandOperation(Next);
            CommLast = new CommandOperation(Last);
            //改变下拉列表索引  触发的命令
            CommPageCount = new CommandOperation(parameter =>
            {

                PageCount = Convert.ToInt32(parameter);
                Init();
            });
            TotalCount = stuDao.GetTotalCount;
            PageCount = 20;
            Init();
        }
        void Init()
        {

            TotalPage = (totalCount / pageCount) * pageCount < totalCount ? totalCount / pageCount + 1 : totalCount / pageCount;
            CurrentPage = 1;
            CurrentStart = 1;
            CurrentEnd = PageCount > TotalCount ? TotalCount : PageCount;
            ListModel = stuDao.GetListStu(currentStart - 1, currentEnd - currentStart + 1);
        }

        #region 分页方法

        private void Next()
        {
            if (CurrentPage < TotalPage)
            {

                CurrentStart = CurrentPage * PageCount + 1;
                CurrentEnd = CurrentStart + PageCount - 1 > TotalCount ? TotalCount : CurrentStart + PageCount - 1;
                CurrentPage++;
                ListModel = stuDao.GetListStu(currentStart - 1, currentEnd - currentStart + 1);
            }
        }

        private void Last()
        {
            CurrentPage = TotalPage;
            CurrentStart = TotalPage > 1 ? (CurrentPage - 1) * PageCount + 1 : 1;
            CurrentEnd = TotalCount;
            ListModel = stuDao.GetListStu(currentStart - 1, currentEnd - currentStart + 1);
        }

        private void Prev()
        {
            if (CurrentPage > 1)
            {
                CurrentPage--;
                CurrentEnd = CurrentStart - 1;
                CurrentStart = (CurrentPage - 1) * PageCount + 1;
                ListModel = stuDao.GetListStu(currentStart - 1, currentEnd - currentStart + 1);

            }
        }

        private void First()
        {
            CurrentPage = 1;
            CurrentStart = 1;
            CurrentEnd = PageCount > TotalCount ? TotalCount : PageCount;
            ListModel = stuDao.GetListStu(currentStart - 1, currentEnd - currentStart + 1);
        }

        #endregion
    }

五、界面绑定

 <Grid x:Name="dataGrid">
        <Grid.RowDefinitions>
            <RowDefinition Height="50"/>
            <RowDefinition Height="*"/>
            <RowDefinition Height="50"/>
        </Grid.RowDefinitions>
        <StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">
            <TextBlock Text="MVVM DataGrid 数据分页 简单案例" FontSize="18" />
        </StackPanel>
        <DockPanel LastChildFill="True" Grid.Row="1">
            <DataGrid ItemsSource="{Binding ListModel}" IsReadOnly="True" AutoGenerateColumns="False">
                <DataGrid.Columns>
                    <DataGridTextColumn Header="序号" Binding="{Binding Id}" Width="2*"/>
                    <DataGridTextColumn Header="姓名" Binding="{Binding Name}" Width="2*"/>
                    <DataGridTextColumn Header="年龄" Binding="{Binding Age}" Width="2*"/>
                    <DataGridTextColumn Header="地址" Binding="{Binding Address}" Width="4*"/>
                </DataGrid.Columns>
            </DataGrid>
        </DockPanel>

        <Grid Margin="0,10,0,0" Grid.Column="1" Grid.Row="3"  >

            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="70"/>
                <ColumnDefinition Width="*"/>
                <ColumnDefinition Width="240"/>
            </Grid.ColumnDefinitions>
            <ComboBox x:Name="combox1" Width="50" Height="20" SelectedIndex="0"  
                                        Margin="0,0,10,0" VerticalAlignment="Top" SelectionChanged="combox1_SelectionChanged" >
                <ComboBoxItem>20</ComboBoxItem>
                <ComboBoxItem>50</ComboBoxItem>
                <ComboBoxItem>100</ComboBoxItem>
            </ComboBox>

            <WrapPanel Grid.Column="1" Grid.RowSpan="2" >
                <WrapPanel >
                    <Button Width="80" Height="20" Command="{Binding CommFirst}" Content="第一页"  />

                    <Button Width="80" Height="20" Command="{Binding CommPrev}" Content="前一页" Margin="10,0"/>

                </WrapPanel>
                <WrapPanel>
                    <TextBlock Text="当前第" VerticalAlignment="Center"/>
                    <TextBox Text="{Binding CurrentPage}"  TextAlignment="Center"  Width="20" Margin="2,0,0,2"/>
                    <TextBlock Text=" 页,共 " VerticalAlignment="Center" />
                    <TextBlock Foreground="Red"  Text="{Binding TotalPage}" VerticalAlignment="Center"/>
                    <TextBlock Text=" 页" VerticalAlignment="Center" />
                </WrapPanel>
                <WrapPanel >
                    <Button Width="80" Height="20" Command="{Binding CommNext}" Content="下一页" Margin="10,0"  />

                    <Button Width="80" Height="20" Command="{Binding CommLast}" Content="末页" Margin="0,0,10,0" />



                </WrapPanel>

            </WrapPanel>
            <WrapPanel Grid.Column="2" Grid.RowSpan="2" >
                <TextBlock Text="显示记录从 " VerticalAlignment="Center"/>
                <TextBlock Text="{Binding CurrentStart}" Foreground="Red"/>
                <TextBlock Text=" 到 "/>
                <TextBlock Text="{Binding CurrentEnd}" Foreground="Red" />
                <TextBlock Text=" 条, 总数 " />
                <TextBlock Text="{Binding TotalCount}" Foreground="Red" />
                <TextBlock Text=" 条" />

            </WrapPanel>



        </Grid>

    </Grid>

 

六、设置DataContext 及处理下拉事件

  public partial class MainWindow : Window
    {
        StuentViewModel viewModel = new StuentViewModel();
        public MainWindow()
        {
            InitializeComponent();
            dataGrid.DataContext = viewModel;
        }
  
        private void combox1_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            string selObj = combox1.SelectedValue.ToString();
            viewModel.CommPageCount.Execute(selObj.Split(':')[1]);

        }
    }

 

源码下载：http://download.youkuaiyun.com/detail/hyh834773759/5023766