创建一个 sqldatareader class

Question

我正在努力创建一个 class，我可以从其他 classes 访问它，它将在我的整个应用程序中访问。我是创建 classes 的新手，感谢任何合乎逻辑的提示。最终，我想访问 "LUSDschoolDates" 中的 "checkpoint1-5" 值作为 "chk1"、"chk2" 等。不确定我是否正确填充数据或更好地使用 List< >??下划线部分表示我正在努力的区域（这基本上是在告诉我我无法访问）以及我喜欢它工作的地方。该项目的目标是创建一个后端管理页面，用户可以在其中插入日期时间数据，并且这些值需要在整个应用程序中都可以访问。

public class checkpoint
{
    public string checkpoint1 { get; set; }
    public string checkpoint2 { get; set; }
    public string checkpoint3 { get; set; }
    public string checkpoint4 { get; set; }
    public string checkpoint5 { get; set; }
}

public class myCheckpoints
{
    public static string Checkpoints()

    {

        using (SqlConnection connection = new SqlConnection(ConfigurationManager.ConnectionStrings["lusdMembership"].ConnectionString))
        {
            SqlCommand cmd = new SqlCommand("SELECT chk1, chk2, chk3, chk4, chk5 FROM checkpoints", connection);
            SqlDataReader reader = cmd.ExecuteReader();
            while (reader.Read())
            {
                checkpoint c = new checkpoint();
                c.checkpoint1 = reader["chk1"].ToString();
                c.checkpoint2 = reader["chk2"].ToString();
                c.checkpoint3 = reader["chk3"].ToString();
                c.checkpoint4 = reader["chk4"].ToString();
                c.checkpoint5 = reader["chk5"].ToString();  
            }
            return Checkpoints();
        }

    }
}


public class LUSDschoolDates
{

    public static DateTime chk1 = new DateTime(checkpoint.checkpoint1);

}

USING A LIST（好像不喜欢"return checkpoint;"） public class 检查点 { public 字符串检查点 1 { 得到；放; } public 字符串检查点 2 { 得到；放; } public 字符串检查点 3 { 得到；放; } public 字符串检查点 4 { 得到；放; } public 字符串检查点 5 { 得到；放; } }

public class myCheckpoints
{
    public List<checkpoint> GetDate(string chDate)

    {

        List<checkpoint> Checkpoints = new List<checkpoint>();
        using (SqlConnection connection = new SqlConnection(ConfigurationManager.ConnectionStrings["lusdMembership"].ConnectionString))
        {
            SqlCommand cmd = new SqlCommand("SELECT chk1, chk2, chk3, chk4, chk5 FROM checkpoints", connection);
            SqlDataReader reader = cmd.ExecuteReader();
            while (reader.Read())
            {
                checkpoint c = new checkpoint();
                c.checkpoint1 = reader["chk1"].ToString();
                c.checkpoint2 = reader["chk2"].ToString();
                c.checkpoint3 = reader["chk3"].ToString();
                c.checkpoint4 = reader["chk4"].ToString();
                c.checkpoint5 = reader["chk5"].ToString();

            }
            return checkpoint;
        }

    }

Answer 1

我为你写了一个 class 连接到 SQL 数据库和 returns 检查点作为 List<T> 其中 T 是一个 class CheckPoint。您还缺少打开和关闭我包含的 SQL 连接的逻辑：

public class CheckPoint
{
    public string CheckPoint1 { get; set; }
    public string CheckPoint2 { get; set; }
    public string CheckPoint3 { get; set; }
    public string CheckPoint4 { get; set; }
    public string CheckPoint5 { get; set; }
}

public class MyCheckpoints
{
    public List<CheckPoint> GetCheckPoins()
    {
        List<CheckPoint> checkpoints = new List<CheckPoint>();

        string connectionString = ConfigurationManager.ConnectionStrings["lusdMembership"].ConnectionString;
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            SqlCommand cmd = new SqlCommand("SELECT chk1, chk2, chk3, chk4, chk5 FROM checkpoints", connection);
            connection.Open();
            using (SqlDataReader reader = cmd.ExecuteReader())
            {
                while (reader.Read())
                {
                    CheckPoint c = new CheckPoint
                    {
                        CheckPoint1 = reader["chk1"].ToString(),
                        CheckPoint2 = reader["chk2"].ToString(),
                        CheckPoint3 = reader["chk3"].ToString(),
                        CheckPoint4 = reader["chk4"].ToString(),
                        CheckPoint5 = reader["chk5"].ToString(),
                    };
                    checkpoints.Add(c);
                }
                connection.Close();
            }
        }
        return checkpoints;
    }
}

下面是从 ASP.NET 调用它的方法：

protected void Page_Load(object sender, EventArgs e)
{
    if(!Page.IsPostBack)
    {
        System.Diagnostics.Debugger.Break();

        MyCheckpoints myCheckpoints = new MyCheckpoints();
        List<CheckPoint> checkPoints = myCheckpoints.GetCheckPoins();
        int count = checkPoints.Count;
    }
}

如果你想让 MyCheckpoints 可以在不同的项目中重复使用，你应该在 Visual Studio 中创建一个 Class 库类型的新项目并复制这个 class 在 Class 库中。

创建一个 sqldatareader class

Creating a sqldatareader class

c#

asp.net

class

sqldatareader