WPF ViewModel分页代码

以下是一个简单的WPF ViewModel分页代码示例：

1. ViewModel类

public class MyViewModel : INotifyPropertyChanged
{
    private ObservableCollection<MyData> _dataList;
    public ObservableCollection<MyData> DataList
    {
        get { return _dataList; }
        set { _dataList = value; OnPropertyChanged("DataList"); }
    }

    private int _pageIndex;
    public int PageIndex
    {
        get { return _pageIndex; }
        set { _pageIndex = value; OnPropertyChanged("PageIndex"); }
    }

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

    private int _totalItemCount;
    public int TotalItemCount
    {
        get { return _totalItemCount; }
        set { _totalItemCount = value; OnPropertyChanged("TotalItemCount"); }
    }

    private int _totalPageCount;
    public int TotalPageCount
    {
        get { return _totalPageCount; }
        set { _totalPageCount = value; OnPropertyChanged("TotalPageCount"); }
    }

    public MyViewModel()
    {
        PageSize = 10;
        PageIndex = 1;
        LoadData();
    }

    private void LoadData()
    {
        //TODO: 获取数据并赋值给DataList，同时更新TotalItemCount和TotalPageCount
    }

    private void OnPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }

    public event PropertyChangedEventHandler PropertyChanged;
}

2. XAML页面

<Grid>
    <DataGrid ItemsSource="{Binding DataList}" AutoGenerateColumns="False">
        <DataGrid.Columns>
            <DataGridTextColumn Header="ID" Binding="{Binding Id}" />
            <DataGridTextColumn Header="Name" Binding="{Binding Name}" />
            <DataGridTextColumn Header="Age" Binding="{Binding Age}" />
        </DataGrid.Columns>
    </DataGrid>
    <StackPanel Orientation="Horizontal" HorizontalAlignment="Center" VerticalAlignment="Bottom">
        <Button Content="上一页" Margin="5" IsEnabled="{Binding PageIndex, Converter={StaticResource IsEnabledConverter}, ConverterParameter=Previous}" Command="{Binding PageIndex, Converter={StaticResource PageIndexConverter}, ConverterParameter=Previous}" />
        <TextBlock Text="{Binding PageIndex}" Margin="5" />
        <Button Content="下一页" Margin="5" IsEnabled="{Binding PageIndex, Converter={StaticResource IsEnabledConverter}, ConverterParameter=Next}" Command="{Binding PageIndex, Converter={StaticResource PageIndexConverter}, ConverterParameter=Next}" />
    </StackPanel>
</Grid>

3. Converter类

public class PageIndexConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value is int pageIndex && parameter is string direction)
        {
            if (direction == "Previous")
            {
                return pageIndex > 1 ? pageIndex - 1 : 1;
            }
            else if (direction == "Next")
            {
                return pageIndex + 1;
            }
        }
        return value;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

public class IsEnabledConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value is int pageIndex && parameter is string direction)
        {
            if (direction == "Previous")
            {
                return pageIndex > 1;
            }
            else if (direction == "Next")
            {
                return pageIndex < (int.MaxValue - 1);
            }
        }
        return false;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

4. 注册Converter和ViewModel

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        DataContext = new MyViewModel();
        Resources.Add("PageIndexConverter", new PageIndexConverter());
        Resources.Add("IsEnabledConverter", new IsEnabledConverter());
    }
}

以上代码实现了一个简单的WPF ViewModel分页功能，通过点击上一页和下一页按钮实现数据的切换，同时显示当前页码。注意需要自行实现LoadData方法获取数据并更新DataList、TotalItemCount和TotalPageCount。