winform treeview遞歸加載數(shù)據(jù)庫(kù)怎么實(shí)現(xiàn)

小億
109
2024-03-30 16:35:06

在Winform中，可以通過(guò)遞歸方式加載數(shù)據(jù)庫(kù)數(shù)據(jù)到TreeView中。下面是一個(gè)簡(jiǎn)單的示例代碼：

首先，創(chuàng)建一個(gè)TreeView控件和一個(gè)Button控件：

TreeView treeView1 = new TreeView();
Button button1 = new Button();
button1.Text = "Load Data";
button1.Click += Button1_Click;

然后，在Button的Click事件中編寫遞歸加載數(shù)據(jù)庫(kù)數(shù)據(jù)的代碼：

private void Button1_Click(object sender, EventArgs e)
{
    treeView1.Nodes.Clear(); // 清空TreeView節(jié)點(diǎn)

    // 連接數(shù)據(jù)庫(kù)并查詢數(shù)據(jù)
    using (SqlConnection conn = new SqlConnection("YourConnectionString"))
    {
        conn.Open();
        SqlCommand cmd = new SqlCommand("SELECT * FROM YourTable", conn);
        SqlDataReader reader = cmd.ExecuteReader();

        // 遞歸加載數(shù)據(jù)到TreeView中
        while (reader.Read())
        {
            LoadDataToTreeView(treeView1.Nodes, reader);
        }
    }
}

private void LoadDataToTreeView(TreeNodeCollection nodes, SqlDataReader reader)
{
    TreeNode node = new TreeNode(reader["ColumnName"].ToString());
    nodes.Add(node);

    // 遞歸加載子節(jié)點(diǎn)數(shù)據(jù)
    using (SqlConnection conn = new SqlConnection("YourConnectionString"))
    {
        conn.Open();
        SqlCommand cmd = new SqlCommand("SELECT * FROM YourTable WHERE ParentID = @ID", conn);
        cmd.Parameters.AddWithValue("@ID", reader["ID"]);
        SqlDataReader subReader = cmd.ExecuteReader();

        while (subReader.Read())
        {
            LoadDataToTreeView(node.Nodes, subReader);
        }
    }
}

在LoadDataToTreeView方法中，首先創(chuàng)建一個(gè)TreeNode對(duì)象并添加到指定的節(jié)點(diǎn)集合中。然后根據(jù)父節(jié)點(diǎn)的ID查詢子節(jié)點(diǎn)數(shù)據(jù)，并遞歸調(diào)用LoadDataToTreeView方法加載子節(jié)點(diǎn)數(shù)據(jù)。

最后，在Button的Click事件中調(diào)用LoadDataToTreeView方法加載根節(jié)點(diǎn)數(shù)據(jù)，實(shí)現(xiàn)數(shù)據(jù)庫(kù)數(shù)據(jù)的遞歸加載到TreeView中。

0 踩