WPF中实现DataGrid行拖拽功能的完整方案
目录
- 前言
- 实现效果
- 核心实现
- 1、定义拖拽行为类
- 2、UI工具类
- 3、XAML中使用
- 实现原理
- 关键特性
- 总结
前言
在wpF应用开发中,DataGrid是一个常用的数据展示控件。然而,原生的DataGrid并不支持行拖拽功能,这在需要调整行顺序的场景中显得尤为不便。
本文将介绍如何实现一个优雅的DataGrid行拖拽功能,使用户可以通过拖拽操作轻松调整行顺序。该方案基于开源项目实现,使用MIT协议的HandyControl样式库,具有良好的可扩展性和实用性。
实现效果
核心实现
1、定义拖拽行为类
public static class DragDropRowBehavior { private static DataGrid dataGrid; private static Popup popup; private static bool enable; private static object draggedItem; public static object DraggedItem { get { return DragDropRowBehavior.draggedItem; } set { DragDropRowBehavior.draggedItem = value; } } // 定义PopupControl附加属性 public static readonly Depend编程客栈encyProperty PopupControlProperty = DependencyProperty.RegisterAttached("PopupControl", typeof(Popup), typeof(DragDropRowBehavior), new UIPropertyMetadata(null, OnPopupControlChanged)); public static Popup GetPopupControl(DependencyObject obj) { return (Popup)obj.GetValue(PopupControlProperty); } public static void SetPopupControl(DependencyObject obj, Popup value) { obj.SetValue(PopupControlProperty, value); } private static void OnPopupControlChanged(DependencyObject depObject, DependencyPropertyChangedEventArgs e) { if (e.NewValue == null || !(e.NewValue is Popup)) { throw new ArgumentException("Popup Control should be set", "PopupControl"); } popup = e.NewValue as Popup; dataGrid = depObject as DataGrid; if (dataGrid == null) return; if (enable && popup != null) { dataGrid.BeginningEdit += OnBeginEdit; dataGrid.CellEditEnding += OnEndEdit; dataGrid.MouseLeftButtonUp += OnMouseLeftButtonUp; dataGrid.PreviewMouseLeftButtonDown += OnMouseLeftButtonDown; dataGrid.MouseMove += OnMouseMove; } else { 编程客栈 dataGrid.BeginningEdit -= OnBeginEdit; dataGrid.CellEditEnding -= OnEndEdit; dataGrid.MouseLeftButtonUp -= OnMouseLeftButtonUp; dataGrid.MouseLeftButtonDown -= OnMouseLeftButtonDown; dataGrid.MouseMove -= OnMouseMove; dataGrid = null; popup = null; draggedItem = null; IsEditing = false; IsDragging = false; } } // 定义Enabled附加属性 public static readonly DependencyProperty EnabledProperty = DependencyProperty.RegisterAttpythonached("Enabled", typeof(bool), typeof(DragDropRowBehavior), new UIPropertyMetadata(false, OnEnabledChanged)); public static bool GetEnabled(DependencyObject obj) { return (bool)obj.GetValue(EnabledProperty); } public static void SetEnabled(DependencyObject obj, bool value) { obj.SetValue(EnabledProperty, value); } private static void OnEnabledChanged(DependencyObject depObject, DependencyPropertyChangedEventwww.devze.comArgs e) { if (e.NewValue is bool == false) throw new ArgumentException("Value should be of bool type", "Enabled"); enable = (bool)e.NewValue; } public static bool IsEditing { get; set; } public static bool IsDragging { get; set; } private static void OnBeginEdit(object sender, DataGridBeginningEditEventArgs e) { IsEditing = true; if (IsDragging) ResetDragDrop(); } private static void OnEndEdit(object sender, DataGridCellEditEndingEventArgs e) { IsEditing = false; } private static void OnMouseLeftButtonDown(object sender, MouseButtonEventArgs e) { if (IsEditing) return; var row = UIHelpers.TryFindFromPoint<DataGridRow>((UIElement)sender, e.GetPosition(dataGrid)); if (row == null || row.IsEditing) return; IsDragging = true; DraggedItem = row.Item; } private static void OnMouseLeftButtonUp(object sender, MouseButtonEventArgs e) { if (!IsDragging || IsEditing) return; dataGrid.Cursor = Cursors.Arrow; var targetItem = dataGrid.SelectedItem; if (targetItem == null || !ReferenceEquals(DraggedItem, targetItem)) { var targetIndex = ((dataGrid).ItemsSource as IList).IndexOf(targetItem); ((dataGrid).ItemsSource as IList).Remove(DraggedItem); ((dataGrid).ItemsSource as IList).Insert(targetIndex, DraggedItem); dataGrid.SelectedItem = DraggedItem; } ResetDragDrop(); } private static void ResetDragDrop() { IsDragging = false; popup.IsOpen = false; dataGrid.IsReadOnly = false; } private static void OnMouseMove(object sender, MouseEventArgs e) { if (!IsDragging || e.LeftButton != MouseButtonState.Pressed) return; if (dataGrid.Cursor != Cursors.SizeAll) dataGrid.Cursor = Cursors.SizeAll; popup.DataContext = DraggedItem; if (!popup.IsOpen) { dataGrid.IsReadOnly = true; popup.IsOpen = true; } Size popupSize = new Size(popup.ActualWidth, popup.ActualHeight); popup.PlacementRectangle = new Rect(e.GetPosition(dataGrid), popupSize); Point position = e.GetPosition(dataGrid); var row = UIHelpers.TryFindFromPoint<DataGridRow>(dataGrid, position); if (row != null) dataGrid.SelectedItem = row.Item; } }
2、UI工具类
public static class UIHelpers { // 查找父元素 public static T TryFindParent<T>(DependencyObject child) where T : DependencyObject { DependencyObject parentObject = GetParentObject(child); if (parentObject == null) return null; T parent = parentObject as T; if (parent != null) return parent; else return TryFindParent<T>(parentObject); } public static DependencyObject GetParentObject(DependencyObject child) { if (child == null) return null; if (child is ContentElement contentElement) { DependencyObject parent = ContentOperations.GetParent(contentElement); if (parent != null) return parent; if (contentElement is FrameworkContentElement fce) return fce.Parent; } return VisualTreeHelper.GetParent(child); } // 更新绑定源 public static void UpdateBindingSources(DependencyObject obj, params DependencyProperty[] propepythonrties) { foreach (DependencyProperty depProperty in properties) { BindingExpression be = BindingOperations.GetBindingExpression(obj, depProperty); if (be != null) be.UpdateSource(); } int count = VisualTreeHelper.GetChildrenCount(obj); for (int i = 0; i < count; i++) { DependencyObject childObject = VisualTreeHelper.GetChild(obj, i); UpdateBindingSources(childObject, properties); } } // 从指定点查找元素 public static T TryFindFromPoint<T>(UIElement reference, Point point) where T : DependencyObject { DependencyObject element = reference.InputHitTest(point) as DependencyObject; if (element == null) return null; else if (element is T) return (T)element; else return TryFindParent<T>(element); } }
3、XAML中使用
<Grid Grid.Row="1" Margin="5"> <!-- 拖拽提示Popup --> <Popup x:Name="popup1" AllowsTransparency="True" IsHitTestVisible="False" Placement="RelativePoint" PlacementTarget="{Binding ElementName=dataGrid1}"> <Textblock Margin="8,0,0,0" VerticalAlignment="Center" FontSize="14" FontWeight="Bold" Text="Dragging..." /> </Popup> <!-- 启用拖拽行为的DataGrid --> <DataGrid x:Name="dataGrid1" controlEx:DragDropRowBehavior.Enabled="True" controlEx:DragDropRowBehavior.PopupControl="{Binding ElementName=popup1}" AutoGenerateColumns="False" ItemsSource="{Binding ListItem}" RowHeaderWidth="60"> <DataGrid.Columns> <DataGridTextColumn Binding="{Binding Column1}" Header="column1" /> <DataGridTextColumn Binding="{Binding Column2}" Header="column2" /> <DataGridTextColumn Binding="{Binding Column3}" Header="column3" /> </DataGrid.Columns> </DataGrid> </Grid>
实现原理
1、拖拽开始:用户按下鼠标左键时,记录被拖拽的行(OnMouseLeftButtonDown
)
2、拖拽过程:鼠标移动时显示提示Popup并更新位置(OnMouseMove
)
3、拖拽结束:释放鼠标时交换行位置(OnMouseLeftButtonUp
)
4、状态管理:使用IsEditing
和IsDragging
标志管理编辑与拖拽状态
5、UI辅助:通过UIHelpers
类在可视化树中查找元素
关键特性
可视化反馈:拖拽时显示"Dragging..."提示
编辑支持:编辑状态下自动禁用拖拽功能
平滑交互:拖拽过程中光标自动切换为"SizeAll"样式
行定位:自动定位鼠标悬停位置的行
总结
本文介绍了WPF DataGrid行拖拽功能的完整实现方案。该方案通过附加行为的方式扩展了DataGrid的功能,使其支持行拖拽操作。
关键点包括:
1、使用附加属性实现功能解耦
2、通过Popup提供拖拽视觉反馈
3、利用UIHelpers工具类简化可视化树操作
4、正确处理编辑与拖拽的冲突
该实现方案具有较好的可复用性,只需在DataGrid上设置附加属性即可启用拖拽功能,无需修改原有业务逻辑。
以上就是WPF中实现DataGrid行拖拽功能的完整方案的详细内容,更多关于WPF DataGrid行拖拽功能的资料请关注编程客栈(www.devze.com)其它相关文章!
精彩评论