C#中DataGridView绑定List<User>后无数据显示的问题

问题说明 #

创建User类并从数据库拉取数据生成User列表后，将列表设置为DataGridView的DataSource，网格无任何数据显示。尝试过BindingSource绑定、手动创建列均无效，但通过Label可确认列表数据正确。

原代码 #

Form1.cs #

namespace Material
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            
            List<User> users = new List<User>();
            Database data = new Database();
            List<User> names = Database.GetFromDB();
            dataGridView1.AutoGenerateColumns = true;
            dataGridView1.DataSource = names;

            label1.Text = names[0].name.ToString();
        } 
    }
}

User.cs #

namespace Material
{
    public class User
    {
        public int id;
        public string name;
        public string email;

        public User(int id, string name, string email)
        {
            this.id = id;
            this.name = name;
            this.email = email;
        }

        public void PrintUser()
        {
            Console.WriteLine(id + " " + name + " " + email);
        }

    }
}

Database.cs #

namespace Material
{
    public class Database
    {
        public static string dbPath = "Data Source= C:\\Users\\Jonathan\\Documents\\csharp\\Material\\Material\\bids.db"; // Path to your database file

        public static void MakeDB()
        {

            SQLiteConnection connection = new SQLiteConnection(dbPath);
            connection.Open(); // This will create the database file if it doesn't exist

            string createTableSql = @"CREATE TABLE IF NOT EXISTS Users2 (
                                Id INTEGER PRIMARY KEY AUTOINCREMENT,
                                Name TEXT NOT NULL,
                                Email TEXT UNIQUE
                              );";

            SQLiteCommand command = new SQLiteCommand(createTableSql, connection);
            command.ExecuteNonQuery();
        }

        public static void AddtoDB(string name)
        {


            SQLiteConnection connection = new SQLiteConnection(dbPath);
            connection.Open(); // This will create the database file if it doesn't exist

            string createTableSql = "INSERT INTO Users (Id, Name, Email) VALUES (Null, @Name, @Email)";


            SQLiteCommand command = new SQLiteCommand(createTableSql, connection);
            command.Parameters.AddWithValue("@Name", name);
            command.Parameters.AddWithValue("@Email", name + "@gmail.com");

            command.ExecuteNonQuery();

        }

        public static List<User> GetFromDB()
        {
            SQLiteConnection connection = new SQLiteConnection(dbPath);
            connection.Open();

            var sql = "SELECT * FROM Users";

            using var command = new SQLiteCommand(sql, connection);
            using var reader = command.ExecuteReader();
            List<User> myObjectList = [];

            if (reader.HasRows)
            {
                while (reader.Read())
                {
                    var id = reader.GetInt32(0);
                    var name = reader.GetString(1);
                    var email = reader.GetString(2);
                    myObjectList.Add(new User(id, name, email));
                 }
            }
            else
            {
                Console.WriteLine("No authors found.");
            }

            return myObjectList;

        }

    }
}

数据库数据 #

解决方法 #

核心问题是User类使用公共字段（field）而非属性（property），DataGridView的数据绑定依赖属性的get/set访问器，无法直接识别公共字段。

修改User类为属性形式 #

namespace Material
{
    public class User
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Email { get; set; }

        public User(int id, string name, string email)
        {
            Id = id;
            Name = name;
            Email = email;
        }

        public void PrintUser()
        {
            Console.WriteLine(Id + " " + Name + " " + Email);
        }
    }
}

额外优化建议 #

1. 保持属性名与数据库列名大小写一致，避免自动生成列时名称不匹配；若需映射可使用[DisplayName]特性。
2. 可选使用BindingSource作为中间层，提升数据绑定灵活性：

var bindingSource = new BindingSource();
bindingSource.DataSource = names;
dataGridView1.DataSource = bindingSource;

3. 完善数据库连接释放逻辑，用using语句包裹SQLiteConnection：

public static List<User> GetFromDB()
{
    List<User> myObjectList = [];
    using (SQLiteConnection connection = new SQLiteConnection(dbPath))
    {
        connection.Open();
        var sql = "SELECT * FROM Users";
        using var command = new SQLiteCommand(sql, connection);
        using var reader = command.ExecuteReader();
        
        if (reader.HasRows)
        {
            while (reader.Read())
            {
                var id = reader.GetInt32(0);
                var name = reader.GetString(1);
                var email = reader.GetString(2);
                myObjectList.Add(new User(id, name, email));
             }
        }
        else
        {
            Console.WriteLine("No authors found.");
        }
    }
    return myObjectList;
}

内容的提问来源于stack exchange，提问作者user22425260