带有动态子项的窗口形式树视图 [英] windows form treeview with dynamic child

问题描述

我正在 C# 中处理 Windows 窗体，以使用数据库中的数据构建树视图.有一个存储过程，它给出了以下信息的列表

I am working on a windows form in C# to build a treeview using data from a database. There is a store procedure which give the list of following info

id - 节点 IDdescription - 要在树视图中显示的值isEndNode - 0 如果它是结束节点；1 如果此节点有子节点

id - node id description - value to be displayed in on the treeview isEndNode - 0 if it is the end node; 1 if this node has child

如果 isEndNode 是 1 那么我必须使用当前节点的 id 调用相同的存储过程来接收它下面的子节点列表.

if isEndNode is 1 then I have to call the same store procedure with id of the current node to receive a list of child node under it.

我已经构建了一个机制来调用存储过程并获取项目列表，但我不确定如何填充树结构.我在想我将第一个列表显示为父节点，当用户单击 + 符号展开时，我将调用存储过程并将新项目作为子节点添加到当前节点.我不确定如何告诉节点它是父节点而不是结束节点.有没有人建造过这样的东西?请帮忙

I have built a mechanism that will call the store procedure and get the list of items but I am not sure how to populate the tree structure. I was thinking I will show the first list as parent nodes and when the user click on + sign to expand I will call the store procedure and add the new item as child to current node. I am not sure how to tell a node that it is a parent node and not the end node. Has any one built something like this? please help

推荐答案

我为您创建了一个示例，您可以在其中了解如何在您的示例中进行操作.

I've created a sample for you, within which you can understand how to do it in yours.

在数据库中创建一个表Employees

Created a table Employees in a database

最初员工的姓名将放在TreeView上

Initially the names of the employees will be put on to the TreeView

展开姓名后，可以查看他们的年龄和电话号码.

When the name is expanded, their Age and PhoneNumber can be viewed.

public Form1()
{
    InitializeComponent();
    initTreeView();  //TreeView without any nodes in it
}

void initTreeView()
{
    SqlConnection con = new SqlConnection();
    con.ConnectionString = _ConnectionString;
    con.Open();
    using (SqlCommand comm = new SqlCommand("Select Name From Employees", con))
    using (SqlDataReader read = comm.ExecuteReader())
        while (read.Read())
        {
            TreeNode tn = new TreeNode(read["Name"].ToString());
            tn.Nodes.Add(new TreeNode());
            treeView1.Nodes.Add(tn);
        }

    treeView1.BeforeExpand += treeView1_BeforeExpand;
}

void treeView1_BeforeExpand(object sender, TreeViewCancelEventArgs e)
{
    TreeNode tNode = e.Node;
    string empName = tNode.Text;
    tNode.Nodes.Clear();
    SqlConnection con = new SqlConnection();
    con.ConnectionString = _ConnectionString;
    con.Open();
    using (SqlCommand comm = new SqlCommand("Select Age, PhoneNumber From Employees Where Name = @empName", con))
    {
        comm.Parameters.AddWithValue("@empName", empName);
        using (SqlDataReader read = comm.ExecuteReader())
            if (read.Read())
            {
                TreeNode nodeAge = new TreeNode(read["Age"].ToString());
                TreeNode nodePhone = new TreeNode(read["PhoneNumber"].ToString());
                tNode.Nodes.AddRange(new TreeNode[] { nodeAge, nodePhone });
            }
    }
}

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