Question

public partial class Piechart : System.Web.UI.Page
{
    private decimal total = 0; // course total
    private decimal registered = 0;
    private decimal regAttend = 0;
    private decimal nRegAttend = 0;
    private int regPer = 0;
    private int regToTotalPer = 0;
    private int nRegPer = 0;
    private int angle = 0;
    private int angle2 = 0;
    private int angle3 = 0;
    private int parTotal = 0;
    //const string G = "SELECT DISTINCT COUNT(Grouping) from Attendance";
   // SqlConnection c = new SqlConnection(@"Data Source=localhost\SQLEXPRESS;Initial Catalog=PSeminar;Integrated Security=true;Trusted_Connection=Yes;MultipleActiveResultSets=true");
    //SqlCommand Command = new SqlCommand(G);


    private string[] Status = new string[2] { "Attend", "Didn't Attend" };
    private string[] Course = new string[] {//items from database};

我想使用sql语句调用项目列表并存储在上面的数组中。我之前正在这样做，因为数组中的项目是硬编码的。现在我想从数据库中检索它，因为只要有新项目，就会自动绘制一个新的饼图。

Answer 1

这是使用ArrayList

执行此操作的方法

ArrayList Course = new ArrayList();
const string query = "SELECT DISTINCT COUNT(Grouping) from Attendance";
const string connectionString = @"Data Source=localhost\SQLEXPRESS;Initial Catalog=PSeminar;Integrated Security=true;Trusted_Connection=Yes;MultipleActiveResultSets=true";
using (SqlConnection cn = new SqlConnection(connectionString))
{
    using (SqlCommand cm = new SqlCommand(query, cn))
    {
        cn.Open();
        SqlDataReader reader = cm.ExecuteReader();
        while (reader.Read())
        {
            Course.Add(reader.GetString(0));
        }
    }
}

//Course.ToArray(); // <-- cast to string array object do use in the pie chart

如何在数组中存储数据库中的项目？

1 个答案: