示例:WPF中TreeView自定义TreeNode泛型绑定对象来实现级联勾选

news2024/11/27 8:47:21

一、目的：在绑定TreeView的功能中经常会遇到需要在树节点前增加勾选CheckBox框，勾选本节点的同时也要同步显示父节点和子节点状态

二、实现

三、环境

VS2022

四、示例

定义如下节点类

   public partial class TreeNodeBase<T> : SelectBindable<T>, ITreeNode
    {
        public TreeNodeBase(T t) : base(t)
        {

        }


        private bool? _isChecked = false;
        public bool? IsChecked
        {
            get { return _isChecked; }
            set
            {
                _isChecked = value;
                RaisePropertyChanged();
                RefreshParentCheckState();
                RefreshChildrenCheckState();
            }
        }


        private void RefreshParentCheckState()
        {
            if (Parent == null)
                return;

            bool allChecked = Parent.Nodes.All(l => l.IsChecked == true);
            if (allChecked)
            {
                Parent.CheckOnlyCurrent(true);
                Parent.RefreshParentCheckState();
                return;
            }

            bool allUnChecked = Parent.Nodes.All(l => l.IsChecked == false);
            if (allUnChecked)
            {
                Parent.CheckOnlyCurrent(false);
                Parent.RefreshParentCheckState();
                return;
            }

            Parent.CheckOnlyCurrent(null);
            Parent.RefreshParentCheckState();

        }

        private void RefreshChildrenCheckState()
        {
            foreach (TreeNodeBase<T> item in Nodes)
            {
                item.CheckOnlyCurrent(IsChecked);
                item.RefreshChildrenCheckState();
            }
        }

        private void CheckOnlyCurrent(bool? value)
        {
            _isChecked = value;
            RaisePropertyChanged("IsChecked");
        }

        public TreeNodeBase<T> Parent { get; set; }

        private ObservableCollection<TreeNodeBase<T>> _nodes = new ObservableCollection<TreeNodeBase<T>>();

        public ObservableCollection<TreeNodeBase<T>> Nodes
        {
            get { return _nodes; }
            set
            {
                _nodes = value;
                RaisePropertyChanged();
            }
        }

        public void AddNode(TreeNodeBase<T> node)
        {
            node.Parent = this;
            Nodes.Add(node);
        }
    }

其中核心方法是如下方法

分别在当前节点勾选有变化时去更新父节点和子节点的勾选状态