TreeView Database Binding Guide

The TreeView control can be bound to a database in two ways, either by using data binding or manual binding.

1. Data binding:
   You can bind the TreeView control to a database through the following steps:
   a. Select the TreeView control in the design view and open the property window.
   b. Locate the “DataSource” property, click the drop-down menu to select a data source (such as a dataset, data table, etc.).
   c. Locate the “DataMember” property, click the drop-down menu to choose the data member to bind (e.g. a field in a data table).
   d. Set the “DisplayMember” and “ValueMember” properties of the TreeView control to specify the displayed text and associated value.
2. Manual binding:
   You can manually bind the TreeView control to the database by following these steps:
   a. Write code to connect to the database and retrieve data.
   b. Add the retrieved data one by one to the nodes of the TreeView control, setting the text and value of each node.
   For example, you can use a loop to add data from the database to the TreeView control.

string connectionString = "连接数据库的连接字符串";
string query = "SELECT * FROM 表名";
using (SqlConnection connection = new SqlConnection(connectionString))
{
    SqlCommand command = new SqlCommand(query, connection);
    connection.Open();
    SqlDataReader reader = command.ExecuteReader();
    while (reader.Read())
    {
        TreeNode node = new TreeNode();
        node.Text = reader["字段名"].ToString();
        node.Value = reader["字段名"].ToString();
        treeView.Nodes.Add(node);
    }
}

The above code is for reference only and needs to be modified and adapted based on actual circumstances.