帶有CheckBoxes的TreeView在c＃中

Question

我有一個帶有c＃復選框的樹視圖，我希望當用戶檢查一個節點時，自動檢查下面級別上的所有節點。 每次用戶檢查某個節點時，是否有人知道如何在沒有在所有樹上運行recorsive fnction的情況下執行此操作？

謝謝

//這個函數返回treeView。

   public TreeView GetTreeView()
    {

        getSubject();
        // fill the treeview with all subjects.
        foreach (Subject subject in subjects)
        {
            //for each root subject fill all the his children.
            if (subject.subjestId == subject.parentSubject)
            {
                TreeNode node = new TreeNode(subject.subjectString, subject.subjestId, subject.subjestId);
                addChild(node, subject.subjestId);
                tv.Nodes.Add(node);
            }
        }
        return tv;
    }
   // for each subject return sub subjects.
   private void addChild(TreeNode node, int parentId)
    {
        foreach (Subject subject in subjects)
        {
            if (subject.parentSubject == parentId && subject.parentSubject != subject.subjestId)
            {
                TreeNode childNode = new TreeNode(subject.subjectString, subject.subjestId, subject.subjestId);
                addChild(childNode, subject.subjestId);
                node.Nodes.Add(childNode);
            }
        }
    }

Answer 1

遞歸。 像這樣：

    bool busy = false;

    private void treeView1_AfterCheck(object sender, TreeViewEventArgs e) {
        if (busy) return;
        busy = true;
        try {
            checkNodes(e.Node, e.Node.Checked);
        }
        finally {
            busy = false;
        }
    }

    private void checkNodes(TreeNode node, bool check) {
        foreach (TreeNode child in node.Nodes) {
            child.Checked = check;
            checkNodes(child, check);
        }

Answer 2

private void treeView1_AfterCheck(object sender, TreeViewEventArgs e) {
  foreach (TreeNode child in e.Node.Nodes) {
    child.Checked = e.Node.Checked;
  }
}

Answer 3

這是一個更好的解決方案

private void trvMenuList_AfterCheck(object sender, TreeViewEventArgs e)
        {
            SetChildrenChecked(e.Node, e.Node.Checked);

        }

  private void SetChildrenChecked(TreeNode treeNode, bool checkedState)
        {
            foreach (TreeNode item in treeNode.Nodes)
            {
                if (item.Checked != checkedState)
                {
                    item.Checked = checkedState;
                }
                SetChildrenChecked(item, item.Checked);
            }
        }

Answer 4

作為一些回答狀態，創建一個遞歸的'set checked to children'函數，然后在樹上調用它AfterCheck。

即使您在代碼中設置了檢查值，該框架也會讓您回調AfterCheck，雖然這在小樹中可能不明顯，但會為您的應用添加大量指數性額外工作。 要避免它，請過濾AfterCheck以僅在用戶觸發新功能時觸發它。

    private void tree_AfterCheck(object sender, TreeViewEventArgs e)
    {
        if (e.Action != TreeViewAction.Unknown)
        {
            SetChildrenChecked(e.Node);
        }
    }

    private void SetChildrenChecked(TreeNode treeNode)
    {
        foreach (TreeNode item in treeNode.Nodes)
        {
            if (item.Checked != treeNode.Checked)
            {
                item.Checked = treeNode.Checked;
            }

            if (item.Nodes.Count > 0)
            {
                SetChildrenChecked(item);
            }                
        }
    }

Answer 5

如果你想在WinForms中這樣做，那么我認為你必須通過遞歸手動完成 - 我不知道更好的方法。