C#前端懒加载sqlserver简单代码

以下是C#前端懒加载SQL Server的简单代码：

//在窗体中定义全局变量
private int pageIndex = 0; //当前页数
private int pageSize = 10; //每页显示的记录数
private int totalCount = 0; //总记录数

private void Form_Load(object sender, EventArgs e)
{
    BindData();
}

private void BindData()
{
    //连接数据库
    string connectionString = "Data Source=.;Initial Catalog=TestDB;Integrated Security=True";
    using (SqlConnection connection = new SqlConnection(connectionString))
    {
        connection.Open();

        //获取总记录数
        string countSql = "SELECT COUNT(*) FROM TestTable";
        SqlCommand countCommand = new SqlCommand(countSql, connection);
        totalCount = (int)countCommand.ExecuteScalar();

        //获取当前页的数据
        string dataSql = "SELECT * FROM (SELECT ROW_NUMBER() OVER(ORDER BY ID) AS RowNumber, * FROM TestTable) AS T WHERE T.RowNumber > @StartIndex AND T.RowNumber <= @EndIndex";
        SqlCommand dataCommand = new SqlCommand(dataSql, connection);
        int startIndex = pageIndex * pageSize;
        dataCommand.Parameters.AddWithValue("@StartIndex", startIndex);
        dataCommand.Parameters.AddWithValue("@EndIndex", startIndex + pageSize);
        SqlDataReader reader = dataCommand.ExecuteReader();

        //绑定数据到DataGridView
        DataTable dataTable = new DataTable();
        dataTable.Load(reader);
        dataGridView1.DataSource = dataTable;

        reader.Close();
        connection.Close();
    }
}

private void dataGridView1_Scroll(object sender, ScrollEventArgs e)
{
    //判断是否到达底部
    if (e.ScrollOrientation == ScrollOrientation.VerticalScroll && e.NewValue == dataGridView1.VerticalScrollBar.Maximum && (pageIndex + 1) * pageSize < totalCount)
    {
        //更新当前页数并重新绑定数据
        pageIndex++;
        BindData();
    }
}

以上代码实现了懒加载的功能，当用户滚动到DataGridView的底部时，会自动加载下一页数据。其中，`BindData()`方法会获取当前页数的数据并绑定到DataGridView，`dataGridView1_Scroll()`方法则是监听滚动事件并在到达底部时更新页数并重新绑定数据。