.NET开发者

在实际应用中为了更好的提高用户的交互效率，我们经常在表格中实现这样的功能，如：单击表头标题，实现按这一列自动排序的功能，在WPF中如何实现这一功能呢？我们知道在WPF中显示GridView要使用ListView，那么，我们可以通过继承ListView实现单击表头自动排序的功能。看下面代码

cs代码：

public class SortableListView : ListView
{
    //最后单击的标题
    private GridViewColumnHeader _lastHeaderClicked = null;
    //默认升序
    private ListSortDirection _lastDirection = ListSortDirection.Ascending;

    //排序字段的附加属性
    public static readonly DependencyProperty SortPropertyNameProperty = DependencyProperty.RegisterAttached("SortPropertyName", typeof(string), typeof(SortableListView));
    // 附加属性的Get方法
    public static string GetSortPropertyName(GridViewColumn obj)
    {
        return (string)obj.GetValue(SortPropertyNameProperty);
    }
    //附加属性的Set方法
    public static void SetSortPropertyName(GridViewColumn obj, string value)
    {
        obj.SetValue(SortPropertyNameProperty, value);
    }

    public SortableListView()
    {
        //注册单击标题事件
        this.AddHandler(
            GridViewColumnHeader.ClickEvent,
            new RoutedEventHandler(GridViewColumnHeaderClickedHandler));
    }

    /// <summary>
    /// 排序方法
    /// </summary>
    /// <param name="sortBy">排序字段</param>
    /// <param name="direction">升序/降序</param>
    private void Sort(string sortBy, ListSortDirection direction)
    {
        ICollectionView dataView =
            CollectionViewSource.GetDefaultView(this.ItemsSource);

        if (dataView != null)
        {
            dataView.SortDescriptions.Clear();
            SortDescription sd = new SortDescription(sortBy, direction);
            dataView.SortDescriptions.Add(sd);
            dataView.Refresh();
        }
    }

    //单击标题调用的方法
    private void GridViewColumnHeaderClickedHandler(object sender, RoutedEventArgs e)
    {
        GridViewColumnHeader headerClicked = e.OriginalSource as GridViewColumnHeader;
        ListSortDirection direction;

        if (headerClicked != null &&
            headerClicked.Role != GridViewColumnHeaderRole.Padding)
        {
            if (headerClicked != _lastHeaderClicked)
            {
                direction = ListSortDirection.Ascending;
            }
            else
            {
                if (_lastDirection == ListSortDirection.Ascending)
                {
                    direction = ListSortDirection.Descending;
                }
                else
                {
                    direction = ListSortDirection.Ascending;
                }
            }
            //获得排序字段
            string sortBy = SortableListView.GetSortPropertyName(headerClicked.Column);
            if (string.IsNullOrEmpty(sortBy))
            {
                sortBy = headerClicked.Column.Header as string;
            }
            //排序操作
            this.Sort(sortBy, direction);

            _lastHeaderClicked = headerClicked;
            _lastDirection = direction;
        }
    }
}

xaml代码：

<local:SortableListView x:Name="lstView">
    <local:SortableListView.View>
        <GridView>
            <GridViewColumn Width="50" Header="ID" DisplayMemberBinding="{Binding ID}" local:SortableListView.SortPropertyName="ID"/>
            <GridViewColumn Width="100" Header="姓名" DisplayMemberBinding="{Binding Name}" local:SortableListView.SortPropertyName="Name"/>
            <GridViewColumn Width="50" Header="年龄" DisplayMemberBinding="{Binding Age}" local:SortableListView.SortPropertyName="Age"/>
            <GridViewColumn Width="200" Header="生日" DisplayMemberBinding="{Binding Birthday}" local:SortableListView.SortPropertyName="Birthday"/>
        </GridView>
    </local:SortableListView.View>
</local:SortableListView>

我们给ListView添加一个附加属性，定义排序的字段名称，通过构造函数注册单击标题的事件，当单击标题时，激发该事件时，进行排序操作。在xaml文件中，我们只要指定排序字段即SortableListView.SortPropertyName属性即可。

代码下载

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