Windows Community Toolkit 4.0 - DataGrid - Part03
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概述
在上面一篇 Windows Community Toolkit 4.0 - DataGrid - Part02 中,我们针对 DataGrid 控件的 Utilities 部分做了详细分享。而在本篇,我们会对控件中最重要的 DataGrid 文件夹中的类做详细的分享。
下面是 Windows Community Toolkit Sample App 的示例截图和 code/doc 地址:
Windows Community Toolkit Doc - DataGrid
Windows Community Toolkit Source Code - DataGrid
Namespace: Microsoft.Toolkit.Uwp.UI.Controls; Nuget: Microsoft.Toolkit.Uwp.UI.Controls.DataGrid;
开发过程
DataGrid 文件夹中是 DataGrid 控件最重要的功能,首先我们还是先来看一下类结构:
包括了 Automation;DataGrid,DataGridColumn,DataGridRow,DataGridCell 控件实现,事件处理参数类和数据类等;
接着我们看几个重要的类和方法:
1. DataGrid.cs
这个类是 DataGrid 控件的主要处理类,功能也是比较复杂,单个类的代码行数是 9001 行,我们只挑两个方法来看一下。其他方法大家有兴趣或用到时可以在 DataGrid.cs 中查阅。
1) DataGrid()
首先看一下 DataGrid 类的构造方法,之所以看这个方法,是想让大家可以更了解 DataGrid 类中变量的初始化方式,这些变量在不同的交互场景下会被赋予不同的值。
public DataGrid() { this.TabNavigation = KeyboardNavigationMode.Once; _loadedRows = new List<DataGridRow>(); _lostFocusActions = new Queue<Action>(); _selectedItems = new DataGridSelectedItemsCollection(this); _rowGroupHeaderPropertyNameAlternative = Properties.Resources.DefaultRowGroupHeaderPropertyNameAlternative; _rowGroupHeaderStyles = new ObservableCollection<Style>(); _rowGroupHeaderStyles.CollectionChanged += RowGroupHeaderStyles_CollectionChanged; _rowGroupHeaderStylesOld = new List<Style>(); this.RowGroupHeadersTable = new IndexToValueTable<DataGridRowGroupInfo>(); _collapsedSlotsTable = new IndexToValueTable<Visibility>(); _validationItems = new Dictionary<INotifyDataErrorInfo, string>(); _validationResults = new List<ValidationResult>(); _bindingValidationResults = new List<ValidationResult>(); _propertyValidationResults = new List<ValidationResult>(); _indeiValidationResults = new List<ValidationResult>(); this.ColumnHeaderInteractionInfo = new DataGridColumnHeaderInteractionInfo(); this.DisplayData = new DataGridDisplayData(this); this.ColumnsInternal = CreateColumnsInstance(); this.RowHeightEstimate = DATAGRID_defaultRowHeight; this.RowDetailsHeightEstimate = 0; _rowHeaderDesiredWidth = 0; this.DataConnection = new DataGridDataConnection(this); _showDetailsTable = new IndexToValueTable<Visibility>(); _focusInputDevice = FocusInputDeviceKind.None; _proposedScrollBarsState = ScrollBarVisualState.NoIndicator; _proposedScrollBarsSeparatorState = ScrollBarsSeparatorVisualState.SeparatorCollapsed; this.AnchorSlot = -1; _lastEstimatedRow = -1; _editingColumnIndex = -1; this.CurrentCellCoordinates = new DataGridCellCoordinates(-1, -1); this.RowGroupHeaderHeightEstimate = DATAGRID_defaultRowHeight; this.LastHandledKeyDown = VirtualKey.None; this.DefaultStyleKey = typeof(DataGrid); HookDataGridEvents(); }
2) ShowScrollBars()
DataGrid 控件中滚动条的处理方法。如果 AreAllScrollBarsCollapsed 为 true,则按照该规则简单处理;如果为 false,先按照 mouse 和 touch 的类型进行判断处理,再根据 UI 设置里的 AreSettingsEnablingAnimations 和 AreSettingsAutoHidingScrollBars 属性来切换滚动条的状态,调用 SwitchScrollBarsVisualStates 方法。
private void ShowScrollBars() { if (this.AreAllScrollBarsCollapsed) { _proposedScrollBarsState = ScrollBarVisualState.NoIndicator; _proposedScrollBarsSeparatorState = ScrollBarsSeparatorVisualState.SeparatorCollapsedWithoutAnimation; SwitchScrollBarsVisualStates(_proposedScrollBarsState, _proposedScrollBarsSeparatorState, false /*useTransitions*/); } else { if (_hideScrollBarsTimer != null && _hideScrollBarsTimer.IsEnabled) { _hideScrollBarsTimer.Stop(); _hideScrollBarsTimer.Start(); } // Mouse indicators dominate if they are already showing or if we have set the flag to prefer them. if (_preferMouseIndicators || _showingMouseIndicators) { if (this.AreBothScrollBarsVisible && (_isPointerOverHorizontalScrollBar || _isPointerOverVerticalScrollBar)) { _proposedScrollBarsState = ScrollBarVisualState.MouseIndicatorFull; } else { _proposedScrollBarsState = ScrollBarVisualState.MouseIndicator; } _showingMouseIndicators = true; } else { _proposedScrollBarsState = ScrollBarVisualState.TouchIndicator; } // Select the proper state for the scroll bars separator square within the GroupScrollBarsSeparator group: if (UISettingsHelper.AreSettingsEnablingAnimations) { // When OS animations are turned on, show the square when a scroll bar is shown unless the DataGrid is disabled, using an animation. _proposedScrollBarsSeparatorState = this.IsEnabled && _proposedScrollBarsState == ScrollBarVisualState.MouseIndicatorFull ? ScrollBarsSeparatorVisualState.SeparatorExpanded : ScrollBarsSeparatorVisualState.SeparatorCollapsed; } else { // OS animations are turned off. Show or hide the square depending on the presence of a scroll bars, without an animation. // When the DataGrid is disabled, hide the square in sync with the scroll bar(s). if (_proposedScrollBarsState == ScrollBarVisualState.MouseIndicatorFull) { _proposedScrollBarsSeparatorState = this.IsEnabled ? ScrollBarsSeparatorVisualState.SeparatorExpandedWithoutAnimation : ScrollBarsSeparatorVisualState.SeparatorCollapsed; } else { _proposedScrollBarsSeparatorState = this.IsEnabled ? ScrollBarsSeparatorVisualState.SeparatorCollapsedWithoutAnimation : ScrollBarsSeparatorVisualState.SeparatorCollapsed; } } if (!UISettingsHelper.AreSettingsAutoHidingScrollBars) { if (this.AreBothScrollBarsVisible) { if (UISettingsHelper.AreSettingsEnablingAnimations) { SwitchScrollBarsVisualStates(ScrollBarVisualState.MouseIndicatorFull, this.IsEnabled ? ScrollBarsSeparatorVisualState.SeparatorExpanded : ScrollBarsSeparatorVisualState.SeparatorCollapsed, true /*useTransitions*/); } else { SwitchScrollBarsVisualStates(ScrollBarVisualState.MouseIndicatorFull, this.IsEnabled ? ScrollBarsSeparatorVisualState.SeparatorExpandedWithoutAnimation : ScrollBarsSeparatorVisualState.SeparatorCollapsed, true /*useTransitions*/); } } else { if (UISettingsHelper.AreSettingsEnablingAnimations) { SwitchScrollBarsVisualStates(ScrollBarVisualState.MouseIndicator, ScrollBarsSeparatorVisualState.SeparatorCollapsed, true /*useTransitions*/); } else { SwitchScrollBarsVisualStates(ScrollBarVisualState.MouseIndicator, this.IsEnabled ? ScrollBarsSeparatorVisualState.SeparatorCollapsedWithoutAnimation : ScrollBarsSeparatorVisualState.SeparatorCollapsed, true /*useTransitions*/); } } } else { SwitchScrollBarsVisualStates(_proposedScrollBarsState, _proposedScrollBarsSeparatorState, true /*useTransitions*/); } } }
2. DataGridCellEditEndedEventArgs.cs
DataGrid 控件中有很多事件处理参数类,我们只看其中一个 DataGridCellEditEndedEventArgs 吧。很显然这个事件包含了 column row 和 editAction 三个变量,大家看到其他时间参数时,可以具体再分析。
public class DataGridCellEditEndedEventArgs : EventArgs { public DataGridCellEditEndedEventArgs(DataGridColumn column, DataGridRow row, DataGridEditAction editAction) { this.Column = column; this.Row = row; this.EditAction = editAction; } public DataGridColumn Column { get; private set; } public DataGridEditAction EditAction { get; private set; } public DataGridRow Row { get; private set; } }
3. DataGridCellCollection.cs
DataGrid 控件中有很多数据类,我们看一个单元格集合类,可以看到集合中有 _cells,Count 变量,Insert 和 RemoveAt 方法等,处理逻辑都比较简单。
internal class DataGridCellCollection { private List<DataGridCell> _cells; private DataGridRow _owningRow; internal event EventHandler<DataGridCellEventArgs> CellAdded; internal event EventHandler<DataGridCellEventArgs> CellRemoved; public DataGridCellCollection(DataGridRow owningRow) { _owningRow = owningRow; _cells = new List<DataGridCell>(); } public int Count { get { return _cells.Count; } } public IEnumerator GetEnumerator() { return _cells.GetEnumerator(); } public void Insert(int cellIndex, DataGridCell cell) { Debug.Assert(cellIndex >= 0 && cellIndex <= _cells.Count, "Expected cellIndex between 0 and _cells.Count inclusive."); Debug.Assert(cell != null, "Expected non-null cell."); cell.OwningRow = _owningRow; _cells.Insert(cellIndex, cell); if (CellAdded != null) { CellAdded(this, new DataGridCellEventArgs(cell)); } } public void RemoveAt(int cellIndex) { DataGridCell dataGridCell = _cells[cellIndex]; _cells.RemoveAt(cellIndex); dataGridCell.OwningRow = null; if (CellRemoved != null) { CellRemoved(this, new DataGridCellEventArgs(dataGridCell)); } } public DataGridCell this[int index] { get { if (index < 0 || index >= _cells.Count) { throw DataGridError.DataGrid.ValueMustBeBetween("index", "Index", 0, true, _cells.Count, false); } return _cells[index]; } } }
4. DataGridCell.cs
DataGrid 控件的单元格类,处理比较简单,我们通过构造方法来看一下类中都涉及到哪些事件的处理;可以看到,光标的一系列处理都有涉及。
public DataGridCell() { this.IsTapEnabled = true; this.AddHandler(UIElement.TappedEvent, new TappedEventHandler(DataGridCell_PointerTapped), true /*handledEventsToo*/); this.PointerCanceled += new PointerEventHandler(DataGridCell_PointerCanceled); this.PointerCaptureLost += new PointerEventHandler(DataGridCell_PointerCaptureLost); this.PointerPressed += new PointerEventHandler(DataGridCell_PointerPressed); this.PointerReleased += new PointerEventHandler(DataGridCell_PointerReleased); this.PointerEntered += new PointerEventHandler(DataGridCell_PointerEntered); this.PointerExited += new PointerEventHandler(DataGridCell_PointerExited); this.PointerMoved += new PointerEventHandler(DataGridCell_PointerMoved); DefaultStyleKey = typeof(DataGridCell); }
总结
这里我们把 DataGrid 的 DataGrid 相关类介绍完成了,代码部分的 CollectionView,Utilities 和 DataGrid 就介绍完了。因为代码本身比较复杂,量也很大,所以我们只挑选了一小部分代码来分享,大家具体用到时可以再具体分析。
接下来我们会就 DataGrid 控件的各种编辑功能,各种自定义功能等做进一步的使用方式的分享。
最后,再跟大家安利一下 WindowsCommunityToolkit 的官方微博:https://weibo.com/u/6506046490, 大家可以通过微博关注最新动态。
衷心感谢 WindowsCommunityToolkit 的作者们杰出的工作,感谢每一位贡献者,Thank you so much, ALL WindowsCommunityToolkit AUTHORS !!!
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