Avalonia treedatagrid使用杂记

这里只对最近使用到的分层树做一些记录，有复选框示例，支持父级选中状态改变子集同步变化

废话不多说，直接上源码

View布局

                <TreeDataGridHeight="710"BorderBrush="Gray"CanUserResizeColumns="False"FontSize="16"Source="{Binding TreeDataGridSource}"><TreeDataGrid.Resources><DataTemplate x:Key="CheckBoxCellTemplate" x:DataType="vm:TreeDataModel"><CheckBox IsChecked="{Binding IsSelected, Mode=TwoWay}" /></DataTemplate></TreeDataGrid.Resources></TreeDataGrid>

model对象

    public class TreeDataModel : INotifyPropertyChanged{private string _name;public string Name{get { return _name; }set{_name = value;OnPropertyChanged(nameof(Name));}}private int? _age;public int? Age{get { return _age; }set{_age = value;OnPropertyChanged(nameof(Age));}}public bool _isSelected;public bool IsSelected{get { return _isSelected; }set{_isSelected = value;OnPropertyChanged(nameof(IsSelected));// 如果是分类节点，更新所有子项的状态if (IsCategory){foreach (var child in Children){child.IsSelected = value;}}}}private string _department;public string Department{get => _department;set{if (_department != value){_department = value;OnPropertyChanged(nameof(Department));}}}private string _category;public bool IsCategory => !string.IsNullOrEmpty(Category);public bool IsExpanded { get; set; } = true;public string Category{get { return _category; }set{_category = value;OnPropertyChanged(nameof(Category));}}private ObservableCollection<TreeDataModel> _children = new ObservableCollection<TreeDataModel>();public ObservableCollection<TreeDataModel> Children{get { return _children; }set{_children = value;OnPropertyChanged(nameof(Children));}}public event PropertyChangedEventHandler? PropertyChanged;protected virtual void OnPropertyChanged([CallerMemberName] string? propertyName = null){PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));}protected bool SetField<T>(ref T field, T value, [CallerMemberName] string? propertyName = null){if (EqualityComparer<T>.Default.Equals(field, value)) return false;field = value;OnPropertyChanged(propertyName);return true;}}

vm 数据刷新逻辑

    private HierarchicalTreeDataGridSource<TreeDataModel> _treeDataGridSource =new HierarchicalTreeDataGridSource<TreeDataModel>(new List<TreeDataModel>());public HierarchicalTreeDataGridSource<TreeDataModel> TreeDataGridSource{get { return _treeDataGridSource; }set{_treeDataGridSource = value;OnPropertyChanged(nameof(TreeDataGridSource));}}private TreeDataModel selectedItem;public TreeDataModel SelectedItem{get => selectedItem;set{selectedItem = value;OnPropertyChanged(nameof(SelectedItem));}}public async void InitTreeData(){List<TreeDataModel> data = new List<TreeDataModel>();for (int i = 0; i < 10; i++){int value = 10 + i;data.Add(new TreeDataModel(){Age = value,Name = $"示例{value}",Department = "测试部",});}for (int i = 0; i < 7; i++){int value = 10 + i;data.Add(new TreeDataModel(){Age = value,Name = $"张三{value}",Department = "研发",});}for (int i = 23; i < 50; i++){int value = 10 + i;data.Add(new TreeDataModel(){Age = value,Name = $"酒香也怕巷子深{value}",Department = "心如止水",});}//聚合形成树形数据集var categoryGroups = data.GroupBy(i =>{// 按照"-"前面的部分分类var dashIndex = i.Department.IndexOf('-');return dashIndex > 0 ? i.Department.Substring(0, dashIndex) : i.Department;});List<TreeDataModel> listData = new List<TreeDataModel>();foreach (var group in categoryGroups){var category = new TreeDataModel { Category = group.Key };foreach (var item in group){category.Children.Add(item);}listData.Add(category);}TreeDataGridSource =new HierarchicalTreeDataGridSource<TreeDataModel>(listData){Columns ={new HierarchicalExpanderColumn<TreeDataModel>(new TextColumn<TreeDataModel, string>("人员",x => x.IsCategory ? $"{x.Category}({x.Children.Count}成员)" : x.Name,GridLength.Auto),x => x.Children,isExpandedSelector: x => x.IsExpanded),new TextColumn<TreeDataModel, int?>("年龄",x => x.Age,GridLength.Auto),new TemplateColumn<TreeDataModel>("","CheckBoxCellTemplate", // 使用自定义模板
                        width: GridLength.Auto),},};TreeDataGridSource.RowSelection.SelectionChanged += (s, e) =>{if (s is TreeDataGridRowSelectionModel<TreeDataModel> selec){if (selec.SelectedItem is TreeDataModel selectModel){SelectedItem = selectModel;}}};}

关键点，

1.数据格式绑定基本都在vm完成treedatagrid数据源集合需要绑定HierarchicalTreeDataGridSource，而不是传统的ObservableCollection

2.行选中时间SelectionChanged，控件不支持直接使用SelectionChanged，需要vm业务层订阅RowSelection来引出SelectionChanged，数据集每次变化都需要重新订阅

3.复选框：

        数据集Columns绑定时其实有CheckBoxColumn列，不过这里演示通过绑定资源键的形式 x:Key="CheckBoxCellTemplate"实现复选框

        父级状态改变影响子集，Avalonia原本的TreeDataGrid并没有对这个实现，但是自己可以通过通过对IsSelected属性变化时，验证IsCategory是否是分类节点 从而更改子集选中状态